# Report on the Radiolaria/Phaeogromia

Order III. PHÆOGROMIA, Haeckel, 1879.
Definition.—Phæodaria with a simple, not bivalved lattice-shell, which assumes very different forms, but is always provided with a peculiar mouth and peristome on the oral pole of the main axis. Central capsule always excentric, placed in the aboral half of the shell-cavity.
Family LXXVIII. Challengerida, John Murray (Pl. 99).
Challengerida, John Murray, 1876, Proc. Roy. Soc. Lond., vol. xxiv. p. 471, pl. xxiv. figs. 1, 2.
Definition.—Phæodaria with a monaxonial, usually ovate or lenticular shell, which exhibits a peculiar, fine, regularly hexagonal, diatomaceous structure, and is usually provided with teeth on the mouth, but without articulated feet. Central capsule excentric, placed in the aboral half of the shell-cavity.
The family Challengerida represent a large, peculiar, and interesting group of Phæodaria, which are, for the most part, inhabitants of great depths, and were perfectly unknown before the discoveries of the Challenger. The first note on these remarkable Radiolaria was given in 1876 by John Murray, in his Preliminary Reports on Work done on board the Challenger (Proc. Roy. Soc. Lond., vol. xxiv. pp. 471, 536, pl. xxiv. figs. 1, 2). He described the peculiar exceedingly beautiful tracery of their shell, similar to that of the Diatomaceæ, the enclosed central capsule coloured by carmine, and the surrounding mass of black-brown pigment lumps (the phæodium). "At times these Challengerida come up with a good deal of sarcode outside of the shell, and two specimens have been seen to throw out elongated pseudopodia" (loc. cit., p. 536). He found also the shells in the Radiolarian ooze of the deep sea. The number of different forms found in the collection of the Challenger is so great, that I can describe in the following pages not less than six genera and fifty-eight species. A part of these have already been figured by Dr. John Murray in the Narrative of the Challenger Expedition, vol. i. p. 226, Pl. A, 1885.
In my first preliminary note on the Phæodaria, in 1879, I gave a stricter definition ​of the Challengerida (Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, 1879, p. 5). But I united at that time the true Challengerida with the Tuscarorida, which, however, are sharply separated by the entirely different structure of their shell. In Plate A given by Dr. John Murray, and mentioned above, figs. 1-14 represent genuine Challengerida, with diatomaceous shell-structure, whilst figs. 15-20 are Tuscarorida, with porcellanous shell-structure. These latter, therefore, are more closely allied to the Circoporida, whilst the Challengerida exhibit a closer affinity to the Medusettida and Castanellida. But the two latter families never possess that peculiar extremely regular and delicate diatomaceous structure which is exhibited only by the Challengerida.
The general form of the Challengerida is rather simple, usually more or less ovate, sometimes nearly triangular, at other times subspherical. In nearly all species, with a few exceptions, the shell is more or less compressed from the two sides, so that its horizontal transverse section is not circular, but elliptical or lanceolate. In many species the shell is more or less lenticular, with a sharp or sometimes keeled margin. This margin lies in the sagittal plane of the body, whilst the two flat sides are right and left. The main axis is always perpendicular, and its oral or anterior pole is marked by the open mouth of the shell; the latter is in the living organism probably the upper pole, whilst the opposite aboral or posterior pole (often marked by large spines) is the lower pole. The dorsal margin of the mouth is usually different from the ventral, and in the majority of species this difference is so striking, that right and left sides of the body may be recognised immediately, the fundamental form being dipleuric or bilaterally-symmetrical. In a few species, however, and mainly in those simplest forms in which the ovate shell has a circular mouth without teeth, and a circular transverse section, that difference is not recognisable, and the ovate shell is monaxonial, as it is in Gromia and Lagena among the Foraminifera (Pl. 99, figs. 19, 20, 22). The size of the shell is in the majority of species between 0.2 and 0.5 mm.; there are, however, some very small species, in which the diameter of the shell is only 0.05 to 0.08, or even less; and some large species, the diameter of which attains 0.8 to 0.9 mm.
The peculiar structure of the siliceous shell-wall, which we call shortly "diatomaceous," and by which the Challengerida differ from all the other Phæodaria, has been already represented very well by Dr. John Murray, in Pl. A. of the Narrative (vol. i. p. 266, figs. 1c-1e, 2a, 4a, 7a, 7b). This elegant diatomaceous structure is extremely similar or nearly identical with that well-known regular structure which we find in the common Diatomaceæ or Bacillariæ. The entire surface of the shell is covered with a very great number of very small pit-like depressions, perfectly regular, circular in form, equal in size, and quincuncial in arrangement. The neighbouring equidistant pits are always surrounded by regular hexagonal frames of equal size, and the prominent fine crests of these frames produce the regular hexagonal tracery, which gives to the shell such a striking similarity to that of the Diatomaceæ. According to ​the different positions to which the focus of the microscope is brought, the hexagonal tracery exhibits a different appearance; either a regular network of equal hexagonal frames, or a lattice with equal and equidistant circular openings, or a combination of three crossed and equidistant systems of parallel lines (crossed at angles of 120°). All the well-known and often discussed optical phenomena which are observed in the valves of the Diatomaceæ, reappear also on the shell of the Challengerida.
To recognise the true nature of this diatomaceous structure, sections and slides of the shell are required, and also fragments of broken shells, the broken margins of which are of special value for obtaining further explanation. The figures given by Dr. J. Murray (loc. cit., Pl. A) have already demonstrated that the pit-like depressions are regular small cavities in the flinty shell-wall, which possess an inner and an outer opening. These intraparietal cavities are either spherical (fig. 7b) or cylindrical (fig. 1d, 4a) or spindle-shaped, with a constriction (fig. 2a). Further accurate examinations probably will show a greater variety in their shape. But each cavity constantly possesses two small openings, one on the outer, and the other on the inner surface of the shell-wall. Closer examination (especially of broken shells and slides) proves the presence of these two openings, which in the smaller species seem to be absent on the first view. I may, therefore, suppose that also in the similar valves of the Diatomaceæ, which exhibit exactly the same structure, an inner and an outer opening are always present in each hexagonal pit, and that the very small size alone prevents them from being recognised. The regular hexagonally-framed cavities in the shell-wall of the Challengerida (probably also of the Diatomaceæ) are therefore genuine pores, differing from the pores of other Radiolaria only in their smaller size and the dilatation of the middle part, which is much wider than the two openings.
The mouth of the shell, its single larger opening, exhibits in the various Challengerida a great variety in form and structure, and offers the best means for separating genera and species. According to its essential shape two different subfamilies and six genera may be distinguished in this family. In the first subfamily, Lithogromida, the mouth is a simple large opening in the wall of the shell on the oral pole of its main axis (Pl. 99, figs. 1-15). In the second subfamily, Pharyngellida, the mouth is prolonged into a cylindrical hollow tube, which is prominent into the shell-cavity, and comparable to the pharynx of the Metazoa in general form and function (Pl. 99, figs. 16-20). In this case we may distinguish an inner and an outer mouth of the tubular pharynx.
In a few forms of both subfamilies the mouth is toothless, smooth, and not armed with prominent external spines or teeth, as in Lithogromia, the simplest form of all (Pl. 99, fig. 22) and in Entocannula (figs. 19, 20). In the great majority of Challengerida, however, the outer opening of the mouth is armed with one or more teeth, usually strong prominent spines (figs. 1-18). Usually the base of these teeth is ​semitubular or a half cylinder, forming a more or less prominent peristome or a proboscis; and always in this case the open concave side of the canal-shaped groove is directed towards the ventral side of the shell, the closed convex side towards the dorsal side. When several teeth arise from the two lateral free margins of the groove, they are also directed towards the ventral side (figs. 2, 12, 17, &c.). Often a deep ventral incision or a guttural constriction separates the base of the proboscis from the genuine shell. The structure of this proboscis or peristome is usually the same as in the diatomaceous shell-wall; but sometimes its lattice-work assumes a different shape.
The opening of the mouth itself is rarely circular, usually it is elliptical or even lanceolate, often triangular. Sometimes two prominent opposite lips may be distinguished as right and left, when the fissure of the mouth is prolonged in a sagittal or longitudinal direction; as upper and lower, when it is prolonged in a frontal or transverse direction. The upper or dorsal lip is always more developed than the lower or ventral; and the entire semitubular proboscis may be regarded as a production of the upper lip. Sometimes the latter attains an extraordinary size and development, the greatest in Challengeria murrayi (Pl. 99, fig. 1).
The teeth of the mouth, which arise from the upper lip, are usually hollow, at least on the base; a prolongation of the shell-cavity arising into the base of the teeth. Their form is very variable, conical, lanceolate, triangular, sabre-shaped, &c. Usually they are more or less curved, and shorter than the radius of the shell; rarely they are straight, and longer than the radius (Pl. 99, figs. 5, 6). More important is their different number, which we have employed for the distinction of subgenera; future observations may prove that they are different genera. The most important are the following cases:—(A.) a single odd dorsal tooth (figs. 5, 16); (B.) two paired lateral teeth (figs. 4, 6, 17); (C.) three teeth, an odd dorsal and two paired lateral (figs. 7, 9, 10); (D.) four paired teeth, two dorsal and two ventral (figs. 3, 13); (E.) five teeth, an odd dorsal and two pairs of lateral (figs. 2, 12); (F.) six teeth in three lateral pairs (fig. 1).
The teeth of the peristome are not the only apophyses which arise from the shell of the Challengerida. In the majority other spines appear on the sagittal margin, which separates the right and left halves of the shell. These marginal spines are characteristic of the genera Challengeron and Porcupinia; they are usually radially directed, straight, conical, sometimes solid, at other times hollow. Their number and arrangement is very variable and serves for the distinction of species; the following differences are the most important:—(A.) a single odd spine on the apical pole of the shell, in the principal axis, opposite to the centre of the mouth (Pl. 99, figs. 6, 7); (B.) two aboral spines, a dorsal and a ventral (figs. 8-10); (C.) a bunch or a crowded group of radial spines on the aboral margin of the shell, usually one larger apical spine surrounded by several smaller dorsal and ventral (figs. 11, 12, 16); (D.) numerous radial spines along the whole sagittal margin of the shell (figs. 13-15).
​The central capsule of the Challengerida is constantly placed in the aboral half of the shell-cavity, whilst its oral half is occupied by the phæodium; the intervals between them and the inner surface of the shell are filled up by the calymma. Frequently from the outer surface of the capsule arise numerous branched streams of sarcode, which pierce the calymma and are directed towards the inside of the shell-wall, where they are united by a thin continuous layer of protoplasm (Pl. 99, fig. 1). The phæodium is usually more voluminous than the capsule and envelops the latter on its anterior or oral face; more rarely the entire capsule is hidden in the phæodium. The phæodella, constituting the latter, are of very different sizes, of variable colour, olive and greenish-brown, red-brown, black-brown or nearly black. In some preparations, stained with carmine, numerous red coloured granula, similar to nuclei, were scattered in the phæodium (compare Murray, loc. cit., Pl. A, figs. 1-14).
The diameter of the central capsule is usually about one-half or one-third as great as that of the enclosing shell (Pl. 99, figs. 1-20). Its form is either spherical or slightly compressed, spheroidal, or sometimes lenticular. The large nucleus has the same form, is about half as broad as the capsule and contains numerous nucleoli. Sometimes the capsule contained two nuclei of equal size, and in a few specimens the shell contained two central capsules, each with a nucleus, so that the Challengerida seem to propagate also by self-division (Pl. 99, fig. 6).
The astropyle, or the large opening of the central capsule, exhibits the usual radiate operculum of the Phæodaria, and the tubular proboscis arising from it. This is constantly placed on the oral or anterior pole of the capsule and directed towards the mouth of the shell. I was never able to discover any parapyle or secondary opening in the central capsule, though numerous and well-preserved specimens of the Challenger collection were accurately examined. It seems therefore that the Challengerida are not Tripylea (as the majority of Phæodaria), but Monopylea with a single opening (like the closely allied Medusettida and Castanellida).
Synopsis of the Genera of Challengerida.
| I. Subfamily Lithogromida. Shell without pharynx or inner prominent tube of the mouth. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell smooth, without adoral teeth and marginal spines, | 693. Lithogromia. |
| I. Subfamily Lithogromida. Shell without pharynx or inner prominent tube of the mouth. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell with adoral teeth, but without marginal spines, | 694. Challengeria. |
| I. Subfamily Lithogromida. Shell without pharynx or inner prominent tube of the mouth. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell with adoral teeth and with marginal spines, | 695. Challengeron. |
| II. Subfamily Pharyngellida. Shell with a pharynx, or an inner cylindrical tube, arising from the mouth and prominent inside. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell smooth, without adoral teeth and marginal spines, | 696. Entocannula. |
| II. Subfamily Pharyngellida. Shell with a pharynx, or an inner cylindrical tube, arising from the mouth and prominent inside. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell with adoral teeth, but without marginal spines, | 697. Pharyngella. |
| II. Subfamily Pharyngellida. Shell with a pharynx, or an inner cylindrical tube, arising from the mouth and prominent inside. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell with adoral teeth and with marginal spines, | 698. Porcupinia. |
Subfamily 1. Lithogromida, Haeckel.
Definition.—Challengerida without pharynx, with a simple mouth, not prolonged into an inner prominent tube.
Genus 693. Lithogromia, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Challengerida without pharynx, without adoral teeth and marginal spines.
The genus Lithogromia and the two following genera represent together the subfamily Lithogromida, comprising those Challengerida in which the mouth of the shell is a simple opening, and not prolonged into a pharynx or an internal prominent tube. Lithogromia may be regarded as the common ancestral form of this family, since it is the simplest of all, and possesses no external apophyses, neither teeth on the mouth, nor spines on the margin of the smooth shell.
1. Lithogromia silicea, n. sp. (Pl. 99, fig. 22).
Shell ovate, one and a half times as long as broad, not compressed. Transverse section circular. Mouth a simple circular opening with smooth edges about one-third as broad as the shell.
Dimensions.—Length of the shell 0.2, breadth 0.15; mouth 0.05.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray, depth 600 fathoms.
2. Lithogromia diatomacea, n. sp. (Pl. 99, fig. 21).
Shell ovate, lenticular, one and one-third times as long as broad, strongly compressed. Transverse section elliptical. Mouth a broad fissure, half as broad as the shell.
Dimensions.—Length of the shell 0.27, breadth 0.2; mouth 0.1.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
3. Lithogromia lenticula, n. sp.
Shell subcircular, lenticular, about as long as broad, strongly compressed. Transverse section lanceolate. Mouth a narrow fissure, one-third as broad as the shell.
Dimensions.—Diameter of the shell 0.15, mouth 0.05.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
​Genus 694. Challengeria, John Murray, 1876, Proc. Roy. Soc. Lond., vol. xxiv. p. 536.}}
Definition.—Challengerida without pharynx, with one or more adoral teeth, but without spines on the sagittal margin.
The genus Challengeria, and the following closely allied Challengeron, differ from the preceding Lithogromia, their ancestral form, in the development of teeth on the mouth of the shell. Challengeron has also radial spines on the sagittal margin, while these are wanting in Challengeria. The latter genus exhibits not less than twenty-one, the former twenty-five species, so that both together make by far the greatest part of the family (containing fifty-eight species). They are also more common and more widely distributed than the four other genera of Challengerida, and many species appear in great numbers in certain localities. With a few exceptions living on the surface, they are all inhabitants of great depths.
Subgenus 1. Challengerantha, Haeckel.
Definition.—Peristome with a single simple tooth, which is neither forked nor branched (Challengeriæ monodontes).
1. Challengeria naresii, John Murray.
Shell circular or nearly circular, strongly compressed, lenticular. Peristome on the dorsal corner with a single simple vertical tooth, which is nearly straight, conical, with two sharp lateral edges on the base, about half as long as the shell.
Dimensions.—Diameter of the shell 0.5 to 0.6, length of the tooth 0.2 to 0.3.
Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, at depths between 1000 and 3000 fathoms.
2. Challengeria xiphodon, n. sp.
Shell circular, nearly spherical, slightly compressed. Peristome on the dorsal corner with a single simple vertical tooth, which is straight, three-sided prismatic, and as long as the shell.
Dimensions.—Diameter of the shell 0.1 to 0.13, length of the tooth 0.1 to 0.12.
Habitat.—Tropical Atlantic, Stations 349 to 352, surface.
​3. Challengeria sigmodon, n. sp.
Shell circular, nearly spherical, slightly compressed. Peristome with a single simple tooth, which is S-shaped, more or less curved, and about one-third as long as the shell.
Dimensions.—Diameter of the shell 0.3 to 0.4, length of the tooth 0.1 to 0.14.
Habitat.—North Pacific, Station 231, depth 2250 fathoms.
4. Challengeria tritonis, n. sp. (Pl. 99, fig. 5).
Shell ovate, slightly compressed. Peristome with a single simple tooth, which is vertical, straight, slenderly conical, and about half as long as the shell.
Dimensions.—Diameter of the shell 0.15 to 0.2, length of the tooth 0.1 to 0.12.
Habitat.—North Atlantic, Færöe Channel, Gulf Stream, in great numbers, in depths from 100 to 600 fathoms. (Expedition of H.M.S. "Triton," 1882), John Murray.
5. Challengeria pyramidalis, n. sp.
Shell slenderly ovate, one and a half times as long as broad, slightly compressed. Peristome with a single, simple, large tooth, which is three-sided pyramidal, vertical, straight, and longer than half the shell.
Dimensions.—Length of the shell 0.6 to 0.8, breadth 0.4 to 0.5; length of the tooth 0.4 to 0.5.
Habitat.—South Atlantic, Station 318, depth 2040 fathoms.
6. Challengeria cyrtodon, n. sp.
Shell ovate, lenticular, strongly compressed. Peristome with a single simple tooth, which is crescent-shaped, curved over the mouth, and about half as long as the shell.
Dimensions.—Length of the shell 0.4 to 0.5, breadth 0.3 to 0.4; length of the tooth 0.2 to 0.25.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
Subgenus 2. Challengeretta, Haeckel.
Definition.—Peristome with a forked or bifid tooth, or with two parallel lateral teeth (Challengeria diodontes).
7. Challengeria sloggettii, John Murray (Pl. 99, fig. 4).
Shell triangular, strongly compressed, with three rounded corners, or nearly semicircular; its aboral margin straight, horizontal, longer than the convex, dorsal, and ventral margins. Peristome ​with two parallel, triangular pointed teeth, which are obliquely ascending, lamellar, with inflated ovate base, and about as long as the shell-radius.
Dimensions.—Diameter of the shell 0.2 to 0.3, length of the teeth 0.1 to 0.15.
Habitat.—Tropical Atlantic, Stations 347, 348, depth 2250 to 2450 fathoms.
8. Challengeria harstoni, John Murray.
Shell subcircular or somewhat triangular, with convex margins. Peristome with two parallel, slender, lanceolate teeth, which are obliquely ascending, and about half as long as the shell-radius.
Dimensions.—Diameter of the shell 0.15 to 0.18, length of the teeth 0.04 to 0.05.
Habitat.—North Pacific, Station 231, depth 2250 fathoms.
9. Challengeria campbelli, John Murray.
Shell cordate, nearly triangular, compressed, with blunt apex. Peristome in the excavated middle of the broad base, with two short, parallel, triangular teeth. This species is very similar to Porcupinia cordiformis (Pl. 99, fig. 16), but differs from it in the absence of an internal pharynx and of external apical spines.
Dimensions.—Diameter of the shell 0.2 to 0.24; length of the teeth 0.03 to 0.05.
Habitat.—South Atlantic, Stations 332 to 335, depth 1425 to 2200 fathoms.
10. Challengeria thomsoni, John Murray.
Shell ovate, slightly compressed, with rounded apical pole. Peristome semitubular, obliquely ascending, nearly straight, in the lower half an open half-cylinder, in the upper half forked, with two parallel, thin, oblique teeth. Sometimes a third small (dorsal) tooth is developed.
Dimensions.—Length of the shell 0.3 to 0.35, breadth 0.2 to 0.25; length of the peristome 0.08 to 0.12.
Habitat.—South Atlantic, Stations 318 to 330, surface, and in depths from 1900 to 2900 fathoms.
11. Challengeria bidens, n. sp.
Shell ovate, strongly compressed, lenticular. Peristome with two curved, long and thin bristle-shaped teeth, which are obliquely inclined over the mouth, and longer than the radius of the shell.
Dimensions.—Length of the shell 0.12 to 0.18, breadth 0.1 to 0.14; length of the teeth 0.08 to 0.1.
Habitat.—Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.
​12. Challengeria havergalli, John Murray.
Shell subspherical, slightly compressed. Peristome semitubular, slender, somewhat curved, in the lower half a simple half-cylinder, in the upper half forked, with two divergent teeth, nearly as long as the shell.
Dimensions.—Diameter of the shell 0.1 to 0.15, length of the peristome 0.08 to 0.12.
Habitat.—South Pacific, Station 300, depth 1375 fathoms.
13. Challengeria elephas, n. sp.
Shell ellipsoidal, not compressed. Peristome very similar to that of Challengeron diodon (Pl. 99, fig. 6), from which this species differs mainly in the absence of an apical spine, and in a more constricted mouth. The two conical teeth of the mouth are very large, nearly as long as the shell, straight, and almost parallel, each tooth has a large hole on the thickened base.
Dimensions.—Diameter of the shell 0.22, length of the teeth 0.2.
Habitat.—Indian Ocean, Cocos Islands (Rabbe), surface.
Subgenus 3. Challengerilla, Haeckel.
Definition.—Peristome with three teeth or trifid, with an odd dorsal and two paired lateral teeth (Challengeriæ triodontes).
14. Challengeria macleari, John Murray.
Shell subcircular, lenticular, with a sharp marginal edge. Peristome semitubular, an oblique half-cylinder, with three divergent, short, triangular teeth; the dorsal odd tooth nearly vertical, the paired lateral teeth subhorizontal. Length of the peristome about one-third or one-fourth of the diameter of the shell.
Dimensions.—Diameter of the shell 0.25 to 0.35, length of the peristome 0.1 to 0.12.
Habitat.—South Atlantic, Stations 325 to 332, depth 1715 to 2900 fathoms.
15. Challengeria tridens, n. sp.
Shell subspherical, slightly compressed. Peristome about as long as the radius of the shell, with three diverging and obliquely descending teeth; the dorsal odd tooth twice as long as the paired lateral teeth.
Dimensions.—Diameter of the shell 0.08 to 0.12, length of the peristome 0.05 to 0.07.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray.
​16. Challengeria trigona, Haeckel.
Shell triangular, with three rounded corners; the two lateral sides nearly straight, equal, the aboral side more or less convex and somewhat shorter. Peristome a curved half-tube (often longer than in Murray's figure), one-third to one-half as long as the shell, with three short triangular diverging and ascending teeth of equal length.
Dimensions.—Length of the shell 0.25 to 0.3, breadth 0.2 to 0.25; length of the peristome 0.08 to 0.12.
Habitat.—South Atlantic, Stations 332 to 335, depth 1425 to 2200 fathoms.
17. Challengeria trifida, n. sp.
Shell ovate, more or less compressed, about two-thirds as long as broad. Peristome semitubular, obliquely ascending, about one-third as long as the shell, in the lower half simple, in the upper trifid, with three curved divergent teeth; the dorsal odd tooth shorter than the paired lateral teeth.
Dimensions.—Length of the shell 0.3 to 0.36, breadth 0.24 to 0.28.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
Subgenus 4. Challengeromma, Haeckel.
Definition.—Peristome with four to six or more teeth.
18. Challengeria quadridens, n. sp.
Shell subglobose, with nearly circular perimeter. Peristome an oblique short and broad tube, the breadth of which is twice as great as its length and equal to the radius of the shell. Margin of the peristome with four divergent, short, triangular teeth, the two dorsal teeth half as long as the two ventral.
Dimensions.—Diameter of the shell 0.22 to 0.24, breadth of the peristome 0.1.
Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms.
19. Challengeria bromleyi, n. sp. (Pl. 99, fig. 3).
Shell ovate, lenticular, strongly compressed. Peristome a broad, trapezoidal, horizontal lamella, the breadth of which is twice as great as its length and nearly equal to the diameter of the shell; its margin with four divergent triangular lamellar teeth, the two dorsal teeth three times as long as the two ventral.
Dimensions.—Length of the shell 0.08 to 0.1, breadth 0.05 to 0.07; breadth of the peristome 0.08.
Habitat.—North Pacific, Stations 244 to 253, surface, and in various depths.
​20. Challengeria wildi, n. sp. (Pl. 99, fig. 2).
Shell subspherical, slightly compressed. Peristome semitubular, curved, as long as the shell-radius; with five curved lamellar teeth, an odd longer dorsal tooth and two pairs of lateral teeth.
Dimensions.—Diameter of the shell 0.12 to 0.18, length of the peristome 0.08 to 0.12.
Habitat.—Tropical Atlantic, Stations 347 to 348, depth 2250 to 2450 fathoms.
21. Challengeria aldrichi, John Murray, Challengeria aldrichi1876, L. N. 27, pl. 24, fig. 2.
Shell subspherical, slightly compressed. Peristome a collar-like curved lamella, the breadth of which is twice as great as its length, and equals the radius of the shell; its margin with six short triangular teeth, two convergent ventral, two external horizontal lateral, and two ascending dorsal.
Dimensions.—Diameter of the shell 0.2, breadth of the peristome 0.1.
Habitat.—North Pacific, Station 244 to 248, depth 2050 to 2900 fathoms.
22. Challengeria murrayi, n. sp. (Pl. 99, fig. 1).
Shell subcircular, lenticular, strongly compressed. Peristome a trapezoidal, curved, collar-like lamella, the breadth of which is three times as great as its length and equal to the diameter of the shell; its margin with six triangular teeth, disposed like the preceding species, but larger.
Dimensions.—Diameter of the shell 0.15, breadth of the peristome 0.15.
Habitat.—North-Western Pacific (south of Japan), Station 231, depth 2250 fathoms.
Genus 695. Challengeron, John Murray, 1879, in litteris et schedulis.
Definition.—Challengerida without pharynx, with one or more teeth on the mouth, and with marginal spines.
The genus Challengeron has in general the same shape as the preceding closely allied Challengeria, but differs from it in the development of radial spines on the sagittal margin of the shell, which in the latter genus is smooth. According to the different number and arrangement of these marginal spines, which give a very singular appearance to them, we divide the twenty-five species of this cosmopolitan genus into four subgenera:—(1) with a single, odd apical spine; (2) with two opposed aboral spines (a dorsal and a ventral); (3) with a bunch of aboral spines; (4) with numerous radial spines along the whole sagittal margin of the shell.
Subgenus 1. Challengeranium, Haeckel.
Definition.—Margin of the shell with a single spine on the apical pole, opposite to the peristome (Challengeriæ caudatæ).
​1. Challengeron monodon, n. sp.
Shell subspherical, slightly compressed, with a single straight conical spine on the apical pole, about as long as the radius. Peristome with a single vertical, straight, conical tooth, diametrically opposite to the apical spine and of the same length. (Similar to Challengeria naresii.)
Dimensions.—Diameter of the shell 0.2 to 0.3, length of the two opposite spines 0.1 to 0.15.
Habitat.—Central Pacific, Stations 270 to 274, depth 2350 to 2925 fathoms.
2. Challengeron cochlear, n. sp.
Shell nearly circular, lenticular, strongly compressed, with a single straight conical spine on the apical pole, about half as long as the radius. Peristome spoon-shaped, obliquely curved and inclined over the mouth, with a single terminal tooth, somewhat longer than the radius.
Dimensions.—Diameter of the shell 0.1, length of the peristome 0.06.
Habitat.—Indian Ocean, Cocos Islands, Rabbe, surface.
3. Challengeron diodon, n. sp. (Pl. 99, fig. 6).
Shell ovate, slightly compressed, with a single straight conical spine on the aboral pole, half as long as the radius. Peristome short and broad, collar-shaped, about twice as broad as long, and half as long as the radius, obliquely inclined over the mouth, with two divergent straight teeth, which are conical and longer than the shell-radius; beyond each tooth a large ovate hole in the wall of the peristome.
Dimensions.—Diameter of the shell 0.08 to 0.1, length of the teeth 0.06 to 0.08.
Habitat.—South-Eastern Pacific, Station 298, depth 2225 fathoms.
4. Challengeron pearceyi, n. sp. (Pl. 99, fig. 7).
Shell ellipsoidal or subspherical, scarcely compressed, with a single straight conical spine on the apical pole, about as long as the diameter. Peristome slender, semitubular, nearly as long as the diameter, somewhat obliquely inclined over the mouth, with three divergent triangular or lanceolate teeth; the dorsal odd tooth about twice as large as the paired lateral teeth.
Dimensions.—Diameter of the shell 0.08 to 0.12, length of the peristome 0.08 to 0.1.
Habitat.—Antarctic Ocean, between Kerguelen and Heard Island, Station 157.
5. Challengeron swirei, John Murray.
Shell subspherical or somewhat ovate, with a single straight conical spine on the apical pole, about as long as the radius. Peristome slender, semitubular, straight and vertical, nearly as long as the shell, with three pointed teeth, an odd longer terminal and two paired shorter lateral.
Dimensions.—Diameter of the shell 0.06 to 0.08, length of the peristome 0.05 to 0.06.
Habitat.—Antarctic Ocean, Station 157, surface, common.
​6. Challengeron triodon, n. sp.
Shell ovate, one and a half times as long as broad, not compressed, with a single short and stout conical spine on the apical pole, shorter than half the radius. Peristome short and broad, collar-shaped, nearly half as broad and one-third as long as the shell, with three divergent terminal teeth, an odd dorsal and two paired lateral.
Dimensions.—Length of the shell 0.25 to 0.3, breadth 0.15 to 0.2; length and breadth of the peristome 0.1.
Habitat.—North Pacific, Station 245, surface.
Subgenus 2. Challengerebium, Haeckel.
Definition.—Margin of the shell with two widely distant aboral spines, opposite in the sagittal plane, a dorsal and a ventral.
7. Challengeron balfouri, John Murray.
Shell subcircular, lenticular, strongly compressed, with two short divergent spines on the apical margin (a dorsal and a ventral). Peristome slender, semitubular, as long as the radius, vertical, in the distal half forked, with two parallel teeth.
Dimensions.—Diameter of the shell 0.08 to 0.16, length of the peristome 0.04 to 0.08.
Habitat.—North Atlantic, Stations 353 to 354, Hebrides, surface.
8. Challengeron golfense, n. sp.
Shell ovate, lenticular, compressed, with two short divergent spines on the apical margin (a dorsal and a ventral). Peristome slender, semitubular, half as long as the radius, with three terminal teeth, two short, vertically ascending, paired teeth and a larger odd tooth, which is inclined obliquely over the mouth.
Dimensions.—Diameter of the shell 0.15 to 0.2, peristome 0.05 to 0.07.
Habitat.—North Atlantic, Færöe Channel, Gulf Stream, surface and at various depths, John Murray.
9. Challengeron richardsii, n. sp. (Pl. 99, fig. 8).
Shell subcircular, lenticular, strongly compressed, with two stout, divergent, straight spines on the aboral margin (a dorsal and a ventral) which reach the length of the radius. Peristome slender, semitubular, slightly curved, about as long as the radius, with three short, divergent, ​terminal teeth. Mouth obliquely truncate. The dorsal odd tooth is nearly vertical, the two lateral paired teeth almost horizontal.
Dimensions.—Diameter of the shell 0.2 to 0.25, length of the spines and the peristome 0.08 to 0.12.
Habitat.—Antarctic Ocean, Station 157, surface, common.
10. Challengeron fergusoni, n. sp. (Pl. 99, fig. 9).
Shell isosceles triangular, with three slightly convex edges and two short, nearly vertically descending spines on the two corners of the aboral margin. Peristome inversely funnel-shaped, with a deep ventral incision on the base, and three broad, ovate, triangular teeth. The dorsal odd tooth is nearly vertical, whilst the two lateral paired teeth are almost horizontal; therefore the angle between the former and the latter is about a right angle.
Dimensions.—Diameter of the shell 0.2 to 0.3, length of the peristome 0.1.
Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.
11. Challengeron tizardi, John Murray.
Shell nearly equilateral triangular, with concave ventral, convex dorsal and aboral edges, on the two corners of the latter two opposite horizontal spines (a dorsal and a ventral). Peristome auriculate and bilobate, with a deep ventral incision on the base, and three pointed triangular teeth, the upper margins of which are nearly horizontal.
Dimensions.—Diameter of the shell 0.22 to 0.3, length and breadth of the peristome 0.01 to 0.12.
Habitat.—South Atlantic, Stations 332 to 335, depth 1425 to 2200 fathoms.
12. Challengeron triangulum, n. sp. (Pl. 99, fig. 10).
Shell nearly equilateral triangular, with three slightly convex or nearly straight sides, and two opposite obliquely descending and diverging spines on the two corners of the aboral margin. Peristome auriculate and bilobate, with a very thin basal neck and a deep incision on its ventral side; its distal margin is obliquely truncate, and exhibits an odd ascending dorsal tooth and two parallel, paired, descending, lateral teeth.
Dimensions.—Diameter of the shell 0.2 to 0.3; length and breadth of the peristome 0.1 to 0.12.
Habitat.—North Pacific, Stations 244 to 253, depth 2050 to 3125 fathoms.
Subgenus 3. Challengeridium, Haeckel.
Definition.—Margin of the shell smooth on the dorsal and the ventral side, but with three to five or more large spines (or a bunch of spines) on the aboral side; the middle spine is placed in the main axis, and larger than the others.
​13. Challengeron bisternum, n. sp.
Shell subcircular, lenticular, strongly compressed, with three stout conical spines on the aboral pole; the middle spine is placed in the main axis, as long as the radius and three times as long as the two others. Peristome semitubular, straight, vertical, about as long as the radius, with three divergent teeth, the middle of which is odd and twice as large as the two paired lateral teeth.
Dimensions.—Diameter of the shell 0.22; length of the peristome 0.1.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
14. Challengeron heptacanthum, n. sp.
Shell ovate, slightly compressed, with a series of five stout, conical, radial spines on the aboral margin; the middle spine is placed in the main axis and longer than the radius, twice as long as the two next, and three times as long as the more distant spines. Peristome short and broad, collar-shaped, with two large, divergent, straight teeth, each of which is longer than the shell-radius and bears at its base a large hole.
Dimensions.—Length of the shell 0.09 to 0.11, breadth 0.07 to 0.08; length of the teeth 0.07.
Habitat.—Tropical Atlantic, Stations 347, 348, depth 2250 and 2450 fathoms.
15. Challengeron crosbiei, n. sp. (Pl. 99, fig. 11).
Shell ovate, strongly compressed, with a series of seven to nine conical spines on the aboral margin; the middle spine is placed in the main axis, as long as the radius, and much larger than the six or eight other spines. Peristome short and broad, collar-like, with several small spines and two slender, widely distant, conical teeth, which are half as long as the shell, and curved towards one another like a pincer, each with a large hole at its base.
Dimensions.—Length of the shell 0.08 to 0.09, breadth 0.06 to 0.07; length of the two larger teeth 0.04 to 0.05.
Habitat.—Central Pacific, Station 270 to 274, depth 2350 to 2925 fathoms.
16. Challengeron buchanani, n. sp. (Pl. 99, fig. 12).
Shell ovate, slightly compressed, with a terminal comb of nine to twelve conical radial spines, densely crowded on the aboral pole; the middle spine is placed in the main axis, about half as long as the shell and much larger than the others. Peristome subconical, semitubular, recurved, half as long as the shell, with five triangular teeth; the dorsal odd tooth is inclined backwards, the two parallel pairs of lateral teeth directed ventrally.
Dimensions.—Length of the shell 0.15 to 0.18, breadth 0.1 to 0.12; length of the peristome 0.06 to 0.08.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
Subgenus 4. Challengerosium, Haeckel.
Definition.—Margin of the shell dentated or serrated, with a continuous series of numerous short radial spines.
17. Challengeron channeri, John Murray.
Shell subcircular, lenticular, strongly compressed, with fourteen to eighteen slender, straight, radial spines on the margin; the spines are straight, equidistant, cylindrical, and about as long as the radius of the shell. Peristome short, with two parallel, vertical, lateral, straight teeth, which are less than half the length of a spine.
Dimensions.—Diameter of the shell 0.14 to 0.17; length of the spines 0.06 to 0.08.
Habitat.—North Pacific, Station 231, depth 2250 fathoms.
18. Challengeron moseleyi, n. sp. (Pl. 99, fig. 14).
Shell circular, lenticular, strongly compressed, with thirty to forty slender, straight, equidistant, radial spines on the margin, larger and smaller spines alternating; the larger spines are about as long as the radius, the smaller only half as long. Peristome short, tubular, with two divergent ovate or nearly triangular teeth, a dorsal and a ventral, about as long as the shorter marginal spines.
Dimensions.—Diameter of the shell 0.13 to 0.15; length of the larger spines 0.06 to 0.07, of the smaller 0.03 to 0.04.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
19. Challengeron bethelli, John Murray.
Shell subcircular, lenticular, strongly compressed, with numerous (twenty to thirty) short conical spines on the margin (often wanting in the upper part of the dorsal margin). Peristome with a deep labial incision and two parallel triangular lateral teeth, the upper margin of which is horizontal.
Dimensions.—Diameter of the shell 0.2 to 0.25; length of the spines 0.02 to 0.03.
Habitat.—North Pacific, Stations 238, 241 (off Japan), depth between 2300 and 3950 fathoms.
20. Challengeron bathybium, n. sp.
Shell subcircular, lenticular, slightly compressed, with a corona of numerous (thirty to forty or more) short, conical, radial spines on the margin. Peristome helmet-shaped, nearly as long as the ​radius, with two widely divergent, conical, curved teeth, a vertical dorsal and a nearly horizontal ventral tooth.
Dimensions.—Diameter of the shell 0.22; length of the peristome 0.1.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
21. Challengeron johannis, n. sp.
Shell ovate, slightly compressed, with a corona of numerous (forty to sixty or more) short radial spines on the margin, ten to fifteen of them (in the aboral half) are pyramidal, and much larger than the others. Peristome helmet-shaped, about one-third as long as the shell, with a deep bosom and two widely divergent teeth on the concave upper margin, a forked dorsal and a conical ventral.
Dimensions.—Length of the shell 0.13, breadth 0.1; length of the peristome 0.04.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray.
22. Challengeron carpenterii, John Murray.
Shell ovate, with a series of twelve to fifteen short, conical, radial spines on the aboral half of the margin. Peristome slender, semitubular, nearly as long as the shell, in the upper half forked, with two short parallel teeth.
Dimensions.—Length of the shell 0.13 to 0.18, breadth 0.1 to 0.14; length of the peristome 0.1 to 0.12.
Habitat.—Tropical Atlantic, Stations 347 to 348, depth 2250 to 2450 fathoms.
23. Challengeron ciliatum, n. sp.
Shell ovate, slightly compressed, with numerous (forty to fifty or more) short and thin, bristle-shaped, radial spines on the margin. Peristome obliquely truncate, with three curved spines; the dorsal odd spine subvertical, nearly as long as the radius, and much stronger than the two parallel, nearly horizontal, lateral spines.
Dimensions.—Length of the shell 0.15, breadth 0.11; length of the peristome 0.1.
Habitat.—North Pacific, Station 231, depth 2250 fathoms.
24. Challengeron willemoesii, n. sp. (Pl. 99, fig. 13).
Shell broadly-ovate or nearly circular, lenticular, with numerous (fifty to sixty) short and stout, conical, radial spines on the margin, increasing in size towards the aboral pole; the spines are alternately larger and smaller, the largest about half as long as the radius. Peristome helmet-shaped or half conical, longer than the radius of the shell, with two pairs of conical, curved, ​divergent teeth; the terminal teeth are the halves of a forked dorsal tooth and diverge laterally; the lower teeth are nearly horizontal and directed ventrally.
Dimensions.—Diameter of the shell 0.13 to 0.15; length of the peristome 0.07 to 0.1.
Habitat.—Tropical Pacific, Stations 274 to 276, depth 2350 to 2750 fathoms.
25. Challengeron wyvillei, n. sp. (Pl. 99, fig. 15).
Shell ovate, lenticular, strongly compressed, with numerous (forty to fifty) short, conical, radial spines on the margin; the spines are larger on the aboral side and spinulate. Peristome narrow, with two parallel, lateral, lamellar, forked teeth, about as long as the radius; the upper branch of the forks is sabre-shaped, obliquely truncate, subvertical, ciliate, and much broader than the lower nearly horizontal branch, which is directed towards the ventral side and curved upwards.
Dimensions.—Length of the shell 0.12 to 0.16, breadth 0.1 to 0.14; length of the peristome 0.08 to 0.11.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
Subfamily 2. Pharyngellida, Haeckel.
Definition.—Challengerida with a pharynx, or an internal prominent mouth tube.
Genus 696. Entocannula, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Challengerida with a pharynx, without teeth on the mouth, and without marginal spines.
The genus Entocannula and the two following genera represent together the subfamily Pharyngellida, differing from the preceding Lithogromida in the development of a peculiar pharynx, an internal, cylindrical, or funnel-shaped tube, which is conspicuous, leads from the mouth into the shell-cavity, and is provided with an inner and an outer opening. The Pharyngellida are much rarer than the Lithogromida; only ten species have been observed of the former, fifty of the latter. Entocannula is the simplest form of the Pharyngellida, having a smooth shell, without aboral teeth and marginal spines; it differs from Lithogromia only in the possession of the pharynx. One remarkable species is covered entirely with extremely thin, flinty hairs, and may represent therefore a peculiar genus, Trichogromia.
​1. Entocannula circularis, n. sp.
Shell circular or nearly circular, lenticular, strongly compressed. Pharynx cylindrical, one-third or one-fourth as broad as the shell, twice as broad as long, its outer and inner apertures of equal breadth. Surface smooth.
Dimensions.—Diameter of the shell 0.20 to 0.32, of the pharynx 0.07 to 0.09.
Habitat.—North Pacific, Station 250, depth 3050 fathoms.
2. Entocannula subglobosa, n. sp.
Shell circular, nearly spherical, slightly compressed. Pharynx funnel-shaped, truncate, conical, its outer opening twice as broad as the inner. Surface smooth.
Dimensions.—Diameter of the shell 0.25 to 0.28, of the inner mouth 0.05.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
3. Entocannula infundibulum, n. sp. (Pl. 99, fig. 19).
Shell ovate, truncate at the mouth, slightly compressed. Pharynx funnel-shaped, its outer aperture two to three times as broad as the inner. Surface smooth.
Dimensions.—Length of the shell 0.22 to 0.28, breadth 0.2 to 0.25; inner mouth 0.04 to 0.08.
Habitat.—South Atlantic, Station 318, depth 2040 fathoms.
4. Entocannula hirsuta, n. sp. (Pl. 99, fig. 20).
Shell ovate. Pharynx cylindrical, one-fourth as broad as the shell, its inner and outer apertures of equal breadth. The whole surface of the shell, and mainly the outer mouth, is densely covered with thin, curved, siliceous bristles.
Dimensions.—Length of the shell 0.27 to 0.36, breadth 0.2 to 0.3; mouth 0.05 to 0.08.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray, depth 600 fathoms.
Genus 697. Pharyngella, n. gen.
Definition.—Challengerida with a pharynx, and with one or more teeth on the mouth, but without marginal spines.
The genus Pharyngella differs from the preceding Entocannula, its ancestral form, in the development of one or more teeth on the peristome, and exhibits therefore the same relation to it that Challengeria bears to Lithogromia. Only a few species of this genus have been observed, all in the Atlantic.
​1. Pharyngella monoceros, n. sp.
Shell ovate, slightly compressed, with a single large tooth on the dorsal corner of the peristome. The tooth is cylindro-conical, half as long as the shell, straight or slightly curved, and lies in the main axis of the shell. Pharynx cylindrical, straight, half as long as the shell-radius. This species is very similar to Challengeria tritonis (Pl. 99, fig. 5), and to the common cosmopolitan Challengeria naresii, but differs generically from them in the possession of the pharynx.
Dimensions.—Diameter of the shell 0.25 to 0.28; length of the tooth 0.14.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
2. Pharyngella gastrula, n. sp. (Pl. 99, fig. 18).
Shell ovate. Peristome with two parallel, vertical, straight, pointed teeth, which are half as long as the shell-radius. Pharynx of the same length, cylindrical or funnel-shaped, its outer aperture scarcely broader than the inner.
Dimensions.—Length of the shell 0.3 to 36, breadth 0.24 to 0.3; teeth and pharynx 0.07 to 0.09.
Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray, depth 600 fathoms.
3. Pharyngella invaginata, n. sp.
Shell circular, slightly compressed or nearly spherical. Peristome with two parallel, vertical, straight, pointed teeth, which are about as long as the shell-radius. Pharynx of the same length, funnel-shaped; its outer aperture twice as broad as the inner.
Dimensions.—Diameter of the shell 0.2 to 0.22, teeth and pharynx 0.05.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
4. Pharyngella gastræa, n. sp. (Pl. 99, fig. 17).
Shell broad, ovate or nearly circular, lenticular, strongly compressed. Peristome with two parallel, pointed teeth, which are nearly as long as the shell-radius, slightly curved, and obliquely inclined over the mouth. Pharynx half as long, cylindrical, obliquely descending; its outer and inner apertures of equal breadth.
Dimensions.—Diameter of the shell 0.3 to 0.33, teeth 0.12, pharynx 0.06.
Habitat.—South Atlantic, Stations 328 to 334, surface.
Genus 698. Porcupinia, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Challengerida with a pharynx, with teeth on the mouth and marginal spines.
The genus Porcupinia differs from the preceding Pharyngella in the development ​of marginal spines, and exhibits therefore the same relation to it that Challengeron bears to Challengeria. Only two species have been observed; the first of these bears, besides the large marginal spines, numerous flinty bristles on the surface of the shell.
1. Porcupinia aculeata, n. sp.
Shell ovate, one and one-third times as long as broad, slightly compressed, covered with short, bristle-shaped spines over the whole surface, similar to Entocannula hirsuta (Pl. 99, fig. 20). The keeled margin is armed with numerous long and stout radial spines, which are alternately larger and smaller, as in Challengeron moseleyi (Pl. 99, fig. 14); the larger about as long as the radius, the smaller half as long. Peristome with two straight, parallel teeth. Pharynx funnel-shaped, half as long as the radius, its outer aperture twice as broad as the inner.
Dimensions.—Length of the shell 0.24, breadth 0.18; peristome 0.05.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
2. Porcupinia cordiformis, n. sp. (Pl. 99, fig. 16).
Shell heart-shaped, nearly triangular, with a deep, concave bosom at the broad oral base, and a bunch of five to nine divergent spines at the blunt aboral apex, the middle spine (in the main axis) larger than the others. Peristome with two parallel, short, triangular teeth, which are obliquely inclined over the mouth (their upper convex edge nearly horizontal). Pharynx cylindrical, short, curved, and obliquely descending.
Dimensions.—Diameter of the shell 0.2 to 0.25, of the pharynx 0.05 to 0.08.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
Family LXXIX. Medusettida, n. fam. (Pls. 118-120).
Definition.—Phæodaria with a simple, ovate, hemispherical or cap-shaped lattice-shell of peculiar alveolate structure, and with hollow articulate feet surrounding the widely open mouth. Central capsule excentric, placed in the aboral half of the shell-cavity.
The family Medusettida represents a peculiar group of remarkable Phæodaria, which are similar to the Challengerida and Tuscarorida in the general form of the monaxonian shell and its apophyses, but differ from both families in the strange alveolate structure of the shell and of the hollow articulate feet surrounding its mouth. All the forms of this family here described are new, and not a single species was known before the discoveries of the Challenger. The majority seem to be inhabitants of the deep-sea, and occur mainly in those places where other families of Phæodaria (Aulacanthida, Aulosphærida, Cœlodendrida) are also well represented; they are, however, nowhere so common as these latter families. Their long feet and the small delicate ​shell are extremely fragile, so that complete and well-preserved specimens are rare. Some species are among the most admirable forms of Radiolaria, and are similar to small elegant Medusæ, e.g., Medusetta (Pl. 120, figs. 1-4), Gazelletta (Pl. 118, fig. 1), and Gorgonetta (Pl. 119).
The shell of the Medusettida is usually very small and delicate, in comparison to the long, often exceedingly large, feet, which depend from the margin of its mouth. From the size and the weight of these feet, we must suppose that the shell floats in the water in the same position as in the Nassellaria, so that the main axis is vertical, and the open mouth with the feet on its lower pole. The form of the shell exhibits the same varieties as the similar umbrella of the Medusæ. It is usually more or less hemispherical, sometimes flatter, cap-shaped, at other times more highly vaulted, campanulate or ovate. The similarity with the umbrella of a Medusa is so great, that in many species the large lower opening on the mouth of the shell is surrounded by a prominent ring or diaphragm, comparable to the velum of the Craspedotæ or Hydromedusæ (Pl. 120, figs. 3-4).
The structure of the shell, which we term shortly "alveolate," is very remarkable, and seems to be different from that of the other Phæodaria. Its reticulate appearance seems to indicate at first sight the usual lattice-shell, pierced by numerous very small pores (Pl. 118, figs. 1-3). But as soon as we make the shell dry, air always enters into its thin walls, and each apparent pore is found to be a small alveole or a separate compartment, which contains a small bubble of air (Pl. 120, figs. 11, 16). The thin wall of the shell is therefore double, composed of two parallel, very thin lamellæ of silica, which are little distant from one another, and are connected by a network of small rods or septa. This network is rarely regular, with square meshes (Pl. 118, fig. 3), or with hexagonal or triangular meshes (Pl. 116, fig. 2); it is usually irregular, with polygonal meshes (Pl. 120, figs. 11-16). The size of the meshes or alveoles is usually smallest on the aboral apex of the shell, and increases gradually towards the mouth. The largest alveoles are around the mouth, on the velum-shaped peristome, and here the marginal alveoles of the shell pass directly over into the separate alveoles or hollow compartments of the articulate feet (Pl. 118, fig. 1). Probably each alveole is a separate compartment, filled up by jelly, and has a small opening or pore on its inside; this pore is very distinct in the marginal alveoles of some larger species (Pl. 116, fig. 1a; Pl. 120, fig. 14), but I have not been able to recognise it everywhere. Moreover, it often happens that the alveoles are apparently completely closed. In some smaller species the alveolate structure seems to be present only in the peripheral part of the shell, whilst the central part is solid.
The outer convex surface of the shell is usually smooth, sometimes papillate (Pl. 116, fig. 1), at other times studded with small, conical, radial spines (Pl. 118, fig. 1; Pl. 120, figs. 4-11). Prolonged cylindrical spines or tubes are rarely ​scattered over the surface (Pl. 116, figs. 1, 2). In some genera a long vertical or oblique spine is developed from the apex of the shell, and is comparable to the "apical horn" of the Nassellaria (Pl. 118, figs. 2, 3; Pl. 120, figs. 1-4).
The mouth of the shell, or the large opening on the lower pole of its vertical main axis, is usually widely open, circular or polygonal, more rarely constricted. In many species the peristome is broadened and its margin developed in the form of a horizontal diaphragm, which constricts the entrance into the shell-cavity, and is comparable to the velum of the Hydromedusæ (Pl. 120, figs. 1-4). Sometimes the margin of the velum is fringed and bears numerous small dependent filaments of silica, comparable to the marginal tentacles of many Medusæ (Pl. 118, figs. 1, 3; Pl. 120, fig. 16). Rarely the mouth is strongly constricted and prolonged into a narrow, long, cylindrical tube, comparable to a proboscis; its opening is usually fringed (Pl. 116, figs. 1, 2).
The hollow articulate feet, or the large radial apophyses of the peristome, are the most remarkable organs of the Medusettida, and occur in the same form in no other family of Radiolaria. Their number is variable from three to twelve or more, and is here employed for the distinction of genera, as it is rather constant; the most frequent number is four (Medusetta) or six (Gazelletta). The feet are usually cylindrical, much longer than the shell, and more or less curved; more rarely they are straight or slightly compressed. They are always articulate, and divided by numerous transverse parallel septa into hollow compartments or alveoles; the transversely striated appearance of the feet is brought about by these septa. The alveoles have usually the form of short discoidal cylinders, and are broader than long (Pl. 120, figs. 5-13); rarely they are longer than broad (fig. 15). The septa between the alveoles are always perforated by a small opening and usually this opening is prolonged into a shorter or longer tubule, comparable to the siphuncle in the septa of the chambered shells of Cephalopoda; as in these latter, the succeeding siphons are arranged in a continuous series, which lies either in the axis of the foot or parallel to it (Pl. 120, figs. 8, 13, 15). The siphons are directed towards the distal end of the foot, so that, e.g., the siphon which arises from the septum between the ninth and tenth alveole, projects into the cavity of the latter. The communicating cavities of all the alveoles are filled up by jelly. In the dry shells, which are cleaned by hot mineral acids or by fire, and in which, therefore, the jelly is destroyed, the cavities become easily filled by air-bubbles (Pl. 120, figs. 8, 11, 15). Whilst the alveoles of each foot always form a long simple series, this series becomes doubled on the base of the larger feet, where they are broadened, and pass over into the compartments of the peristome (Pl. 122, figs. 10, 11, 14). The terminal alveole of each foot is closed.
The feet of the Medusettida are rarely quite simple and smooth (Pl. 120, figs. 1, 5, 7, 10, &c.). Usually they are armed with numerous spines or with elegant pencils of spathillæ. These secondary appendages or branches are also hollow, with a ​thin wall of silex; but they seem usually not to communicate with the alveoles of the foot directly; the cavities of the foot and its appendages are separated by a thin, solid septum. In Medusetta the convex outer edge of each curved foot is studded with a series of simple alveolate branches (Pl. 120, figs. 2-4). In Gazelletta, the feet are usually armed with verticillate or alternate spines, which are either simple or branched (Pl. 120, figs. 11-15); sometimes each branch is elegantly arborescent (Pl. 118, fig. 1). Sometimes the distal end of each branch is armed with a spathilla or a coronet of recurved teeth. The branches attain their highest development in the admirable Gorgonetta (Pl. 119). The twelve feet of this most interesting genus are differentiated into two different and alternating groups, six descending and six ascending. The six upper or ascending feet are arborescent, and each branch is armed at the distal end with a spathilla (figs. 1, 2). The six lower or descending feet are covered with most elegant arborescent pencils or anchor-bearing trees; each terminal branch of a tree is armed with two spathillæ, a smaller terminal and a larger below it (figs. 3, 4). The distal ends of the feet are rarely simple, usually they are forked or branched, or armed with peculiar spathillæ; and sometimes these terminal branches are very large (Pls. 118, 119).
The central capsule of the Medusettida is usually subspherical or somewhat lenticular, and hidden in the aboral or upper part of the shell-cavity, whilst its oral or lower part is filled up by the phæodium (Pl. 120, figs. 2, 9, 10, 11). Sometimes the phæodium is very large and prominent at the aperture of the mouth (Pl. 118, figs. 2, 3; Pl. 119, fig. 1). The nucleus is usually ellipsoidal, half as large as the central capsule, and includes numerous nucleoli. The membrane of the central capsule seems in all Medusettida to possess only one opening, the astropyle or main-opening with a radiate operculum and proboscis, placed at the lower or oral pole (Pl. 120, fig. 2). I have never been able to observe any secondary opening or parapyle. The free space between the shell wall and the capsule is filled up by the calymma, which also includes the phæodium. The jelly of the calymma is probably in direct continuity with the jelly which fills up the alveoles of the shell-wall and of the articulate feet.
Synopsis of the Genera of Medusettida.
| I. Subfamily Euphysettida. Peristome of the shell with a corona of three or four feet. Apex of the shell (usually) with an apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$ | Three equal feet, | 699. Cortinetta. |
| I. Subfamily Euphysettida. Peristome of the shell with a corona of three or four feet. Apex of the shell (usually) with an apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$ | Four equal feet, | 700. Medusetta. |
| I. Subfamily Euphysettida. Peristome of the shell with a corona of three or four feet. Apex of the shell (usually) with an apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$ | One large and three small feet, | 701. Euphysetta. |
| II. Subfamily Gazellettida. Peristome of the shell with six to twelve or more feet. Apex of the shell (usually) without apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Six descending feet, | 702. Gazelletta. |
| II. Subfamily Gazellettida. Peristome of the shell with six to twelve or more feet. Apex of the shell (usually) without apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Six descending and six ascending alternating feet, | 703. Gorgonetta. |
| II. Subfamily Gazellettida. Peristome of the shell with six to twelve or more feet. Apex of the shell (usually) without apical horn. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Numerous (ten to twenty or more) descending feet, | 704. Polypetta. |
Genus 699. Cortinetta, n. gen.
Definition.—Medusettida with three articulate feet on the peristome.
The genus Cortinetta comprises Medusettida which exhibit the minimum number of feet, three, and which therefore may be compared to the tripodal Nassellaria (Cortina, Cortiniscus, Tripodiscus, &c.). This similarity is the greater, as in the few observed species an apical horn is developed (as also in the following genus). The three feet are in the two species observed of equal size and similar form, and equidistant, so that they cannot be distinguished as an odd caudal and two paired lateral feet, as in the similar Nassellaria.
1. Cortinetta tripodiscus, n. sp. (Pl. 117, fig. 7).
Shell campanulate, covered with numerous curved ascending bristles, with a prominent annular velum on the peristome, similar to that of Medusetta craspedota. (Pl. 120, fig. 4). Feet equal, widely divergent and equidistant, somewhat longer than the shell, slightly curved, and covered on their convex outer edge with a series of short lateral branches, the three ramules of which bear a spathilla. Apical horn conical, straight, about as long as the shell, also covered with curved bristles.
Dimensions.—Length of the shell 0.14, breadth 0.11; length of the feet 0.16, of the apical horn 0.11.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
2. Cortinetta cortiniscus, n. sp.
Shell campanulate, subspherical, thorny, with a prominent annular velum on the peristome. Feet equal, very large, widely divergent, about three times as long as the shell and studded with arborescent branches, similar to those of Gazelletta drymonema (Pl. 118, fig. 1). Apical horn slender, conical, straight, thorny, twice as long as the shell.
Dimensions.—Length of the shell 0.18, breadth 0.16; length of the feet 0.5 to 0.6, of the apical horn 0.33.
Habitat.—Central Pacific, Station 274, depth 2750 fathoms.
Genus 700. Medusetta, n. gen.
Definition.—Medusettida with four equidistant articulate feet of equal size on the peristome.
The genus Medusetta comprises those forms of the family which bear on the peristome four equal radial feet, and therefore exhibit a striking similarity to many ​small Medusæ (e.g., Codonium, Tiara, Sarsia, &c.). This similarity is the greater, as usually the four feet are elegantly curved and the entrance in the shell-cavity partly closed by a marginal diaphragm, comparable to the velum of the Craspedotæ or Hydromedusæ. In all the species observed the apex of the shell bears a slender vertical or curved spine, comparable to the apical horn of the Nassellaria. In most species the feet bear on their convex outside a series of teeth or branches, which are also alveolate.
1. Medusetta codonium, n. sp. (Pl. 120, fig. 1).
Shell ovate, smooth, twice as broad as the constricted mouth. Apical horn about as long as the shell, nearly straight, smooth. Feet cylindrical, smooth, irregularly curved, about as long as the shell.
Dimensions.—Length of the shell 0.08, breadth 0.05.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
2. Medusetta tiara, n. sp.
Shell campanulate, smooth, about as long as broad, and three times as broad as the constricted mouth, which is surrounded by a horizontal broad ring, like the velum of a Hydromedusa. Apical horn conical, straight, half as long as the shell. Feet divergent, irregularly curved, twice as long as the shell.
Dimensions.—Length of the shell 0.07, breadth 0.06.
Habitat.—North Atlantic (Færöe Channel), John Murray, surface.
3. Medusetta minima, n. sp.
Shell slenderly ovate, smooth, about twice as long as broad, twice as broad as the constricted mouth. Apical horn straight, vertical, of the same length. Feet somewhat longer, very thin, slightly curved at the base, in the distal half nearly parallel and descending vertically.
Dimensions.—Length of the shell 0.06, breadth 0.03.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
4. Medusetta quadrigata, n. sp. (Pl. 120, fig. 2).
Shell ovate, campanulate, smooth, little broader than the wide open mouth. Apical horn longer than the shell, more or less curved, smooth. Feet cylindrical, about as long as the shell, strongly curved and somewhat spirally revoluted, with a series of short curved teeth on the abaxial margin.
Dimensions.—Length of the shell 0.07 to 0.09, breadth 0.04 to 0.06.
Habitat.—North Pacific (off Japan), Stations 231 to 237, surface.
​5. Medusetta tetranema, n. sp. (Pl. 120, fig. 3).
Shell campanulate, conical, smooth, nearly twice as broad as the constricted mouth, without prominent velum. Apical horn somewhat shorter, straight, conical, thorny. Feet strongly curved inwards, convergent, twice as long as the shell, each with four to six strong, ascending, alveolate branches on the abaxial margin.
Dimensions.—Length of the shell 0.07 to 0.09, breadth 0.05 to 0.07.
Habitat.—Tropical Atlantic, Station 352, surface.
6. Medusetta spiralis, n. sp.
Shell hemispherical, thorny, with wide open mouth. Apical horn straight, vertical, thorny, twice as long as the shell; feet cylindrical, three times as long as the shell, spirally convoluted around the vertical axis of the shell, with a series of recurved teeth on the abaxial margin.
Dimensions.—Length of the shell 0.05, breadth 0.08.
Habitat.—Central Pacific, Stations 271 to 272, surface.
7. Medusetta craspedota, n. sp. (Pl. 120, fig. 4).
Shell campanulate or nearly spherical, spiny, twice as broad as the constricted mouth, which is surrounded by a funnel-shaped truncate velum. Apical horn conical, straight, spiny, half as long as the shell. Feet strongly curved, longer than the shell, with a series of short conical spines on the abaxial side.
Dimensions.—Length of the shell 0.06, breadth 0.06.
Habitat.—North Pacific, Station 239, surface.
Genus 701. Euphysetta, n. gen.
Definition.—Medusettida with four articulate feet on the peristome, one odd very large, and three small or rudimentary feet.
The genus Euphysetta agrees with the preceding Medusetta in the possession of four articulate feet; but whilst these in the latter are of equal size and similar shape, in the former a single odd foot only is developed, and very large, whilst the three others are rudimentary and very small. Euphysetta exhibits therefore the same relation to Medusetta that the Euphysidæ (Euphysa, Steenstrupia, &c.) bear to the Sarsiadæ (Codonium, Sarsia), among the Hydromedusæ (compare my System der Medusen, 1879, vol. i. p. 12).
​1. Euphysetta staurocodon, n. sp. (Pl. 118, fig. 2).
Shell ovate, nearly as broad as long, smooth, with an oblique, slender, conical, apical horn of the same length. The larger odd foot cylindrical, curved, somewhat longer than the shell, with three diverging branches at the distal end. The three smaller feet very short, representing the form of a regular rectangular cross.
Dimensions.—Length of the shell 0.15, breadth 0.14.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
2. Euphysetta hybocodon, n. sp.
Shell ovate, one and one-third times as long as broad, smooth, with an oblique, stout, conical horn of half the length. The larger odd foot cylindrical, curved, twice as long as the shell, with a few pairs of short lateral branches and forked distal end. The three smaller feet half as long as the shell, thorny.
Dimensions.—Length of the shell 0.16, breadth 0.12.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
3. Euphysetta amphicodon, n. sp. (Pl. 118, fig. 3).
Shell subspherical, smooth, with a short, oblique, conical, apical horn. The larger odd foot cylindrical, nearly straight, as long as the shell, with a few short lateral branches, at the distal end forked. The three smaller feet were in one specimen observed forked, in another (the specimen figured) replaced by nine small thorns.
Dimensions.—Length of the shell 0.11, breadth 0.13.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
Genus 702. Gazelletta, John Murray, 1876 (in litteris).
Definition.—Medusettida with six articulate feet on the peristome.
The genus Gazelletta is by far the most common of all Medusettida, and some species seem to be widely distributed, or even cosmopolitan. The number of species, too, is in this genus much larger than in all the other genera of this family. It differs from the latter in the possession of six feet, which number is very constant in the majority of species; in some species, however, single specimens are not rarely found which possess five or seven feet instead of six. Usually the six feet are rather regularly formed and disposed, and diverge downwards; but sometimes there is more or less ​irregularity in their shape and arrangement. In the majority of species the feet are very long, curved, and armed in a very various manner, so that four subgenera may be distinguished, according to the armatures.
Subgenus 1. Gazellarium, Haeckel.
Definition.—Feet simple, smooth, without spines and without terminal branches.
1. Gazelletta hexanema, n. sp. (Pl. 120, fig. 5).
Shell hemispherical, smooth. Feet very long, cylindrical, straight, smooth, widely divergent, without terminal branches.
Dimensions.—Length of the shell 0.03 to 0.04, breadth 0.06 to 0.07; length of the feet 0.1 to 0.2.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.
2. Gazelletta macronema, n. sp. (Pl. 120, figs. 7, 8).
Shell hemispherical, smooth. Feet very long, cylindrical, smooth, in the basal part horizontally expanded, in the distal part strongly curved downwards, without terminal branches.
Dimensions.—Diameter of the shell 0.1 to 0.12, length of the feet 1.2 to 1.6.
Habitat.—Central Pacific, Stations 270 to 274, surface.
3. Gazelletta orthonema, n. sp. (Pl. 120, fig. 10).
Shell hat-shaped, thorny. Feet cylindrical, straight, smooth, widely divergent, without terminal branches.
Dimensions.—Diameter of the shell 0.12 to 0.16, length of the feet 0.3 to 0.5.
Habitat.—Central Pacific, Stations 270 to 274, surface.
4. Gazelletta cyrtonema, n. sp. (Pl. 120, fig. 9).
Shell hat-shaped, thorny. Feet cylindrical, smooth, widely diverging at the base, strongly curved and convergent in the distal part, often semicircular, without terminal branches.
Dimensions.—Diameter of the shell 0.11 to 0.13, length of the feet 0.4 to 0.6.
Habitat.—North Atlantic, Station 354, Canary Islands, surface.
Subgenus 2. Gazellidium, Haeckel.
Definition.—Feet smooth, without lateral spines, but branched at the distal end, or with a bunch of terminal spines.
​5. Gazelletta furcata, n. sp.
Shell flat, cap-shaped, smooth. Feet cylindrical, nearly straight, at the distal end forked, with two divergent, spinulate, terminal branches.
Dimensions.—Length of the shell 0.12, breadth 0.3; length of the feet 0.6 to 0.8.
Habitat.—Western Tropical Pacific, Station 224, surface.
6. Gazelletta bifurca, n. sp. (Pl. 120, fig. 6).
Shell cap-shaped, thorny. Feet nearly straight, widely divergent, cylindrical, smooth, at the distal end twice forked, with four divergent, terminal branches, each of which bears a spathillum with six to eight recurved teeth (sometimes, as in the specimen figured, five or six terminal branches instead of four).
Dimensions.—Diameter of the shell 0.1, length of the feet 0.3 to 0.4.
Habitat.—South Pacific, Station 288, surface.
7. Gazelletta penicillata, n. sp.
Shell campanulate, spiny. Feet cylindrical, strongly curved, smooth, with a bunch of twelve to twenty or more curved spines at the distal end.
Dimensions.—Diameter of the shell 0.08, length of the feet 0.6.
Habitat.—Central Pacific, Station 266, surface.
Subgenus 3. Gazellonium, Haeckel.
Definition.—Feet spiny, armed with simple or branched lateral spines, and with terminal branches of the same shape.
8. Gazelletta pectinata, n. sp.
Shell flat, cap-shaped, thorny, three times as broad as high. Feet straight or slightly curved, cylindrical, widely divergent, with four longitudinal rows of short and simple conical spines, which are directed towards the distal end, and about as long as a single joint of the foot.
Dimensions.—Length of the shell 0.16, breadth 0.5; length of the feet 1.5 to 2.0, breadth 0.03 to 0.05.
Habitat.—North Atlantic, Færöe Channel (John Murray), Hebrides (Mœbius).
9. Gazelletta pinnata, n. sp.
Shell hat-shaped, thorny. Feet cylindrical, strongly curved, pinnate, with two opposite longitudinal rows of simple conical spines, which are slightly curved, directed towards the distal end and opposed in pairs on about each third or fourth joint.
Dimensions.—Diameter of the shell 0.3, length of the feet 1.2 to 1.5.
Habitat.—South Atlantic, Station 325, depth 2650 fathoms.
​10. Gazelletta studeri, n. sp. (Pl. 120, fig. 15).
Shell flat, cap-shaped, thorny. Feet widely divergent, nearly straight and horizontally expanded, with two alternate longitudinal rows of lateral spines, which arise perpendicularly from the foot, are simple, conical, slightly curved, and alternate on the succeeding joints. Ends of the feet constricted, with four to six spines in one row. Dedicated to Professor Studer.
Dimensions.—Diameter of the shell 0.15, length of the feet 0.6 to 0.8.
Habitat.—South Atlantic (east of Patagonia), Station 318, surface.
11. Gazelletta schleinitzii, n. sp. (Pl. 120, figs. 11, 12).
Shell hat-shaped, thorny. Feet cylindrical, nearly straight and horizontally expanded, with four longitudinal rows of equal lateral spines, which arise perpendicularly from the foot and bear at the end three short divergent teeth. The end of the arms bears three forked spines. I name this elegant species in honour of Captain Schleinitz, commander of the German ship "Gazelle," who conducted the deep-sea soundings during the years 1874 to 1876.
Dimensions.—Diameter of the shell 0.12, length of the feet 0.6 to 0.8.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
12. Gazelletta trispathilla, n. sp. (Pl. 120, fig. 13).
Shell flat, cap-shaped, smooth. Feet cylindrical, nearly straight, widely divergent, with longitudinal rows of alternate spines, which arise perpendicularly from the foot and bear at the end three short divergent branches, each with a spathilla of six short teeth.
Dimensions.—Diameter of the shell 0.2 to 0.25, length of the feet 1.2 to 1.5.
Habitat.—North Pacific, Station 235 to 238, surface.
13. Gazelletta robusta, n. sp. (Pl. 120, fig. 14).
Shell flat, cap-shaped, thorny. Feet cylindrical, very stout, slightly curved, covered with short irregularly branched spines; their ends with a bunch of similar spines.
Dimensions.—Diameter of the shell 0.6, length of the feet 2.5 to 3.3.
Habitat.—Central Pacific, Stations 263 to 274, surface.
Subgenus 4. Gazellusium, Haeckel.
Definition.—Feet spiny, armed with simple or branched lateral spines, and with larger terminal branches of a different shape.
​14. Gazelletta dendronema, n. sp. (Pl. 120, fig. 16).
Shell hemispherical, thorny, with a broad, alveolate velum which bears irregular hollow thorns on the inside and on the free margin (fig. 16). Feet divergent, irregularly curved, with scattered arborescent lateral spines, which are irregularly branched, and bear at the distal end of each branch a small spathilla with four to six teeth. The distal ends of the feet are dichotomously branched, with stouter simple fork-branches.
Dimensions.—Length of the shell 0.17, breadth 0.36; length of the feet 0.5 to 0.7.
Habitat.—North Pacific, Station 252, surface.
15. Gazelletta melusina, n. sp. (Pl. 118, fig. 1).
Shell campanulate, spiny. Feet divergent, strongly curved, with scattered arborescent lateral spines, which are richly and dichotomously branched, with thin, simple, terminal branches. The distal ends of the feet bear three or four much larger and stouter branches, which are again dichotomously branched.
Dimensions.—Length of the shell 0.2, breadth 0.15; length of the feet 0.5 to 0.8.
Habitat.—South Pacific, Station 293, depth 2025 fathoms.
Genus 703. Gorgonetta, n. gen.
Definition.—Medusettida with twelve articulate feet on the peristome, six ascending and six alternate descending.
The genus Gorgonetta is the most highly developed of all hitherto observed Medusettida, and belongs to the most remarkable forms of Radiolaria. Its general shape is very similar to that of a larva of a Geryonia or Carmarina, in which six interradial larval tentacles are directed upwards, six alternating perradial permanent tentacles downwards. The six ascending feet are in all the four species observed smaller, more or less branched, and armed with spathillæ. The six descending feet are much larger and covered with very elegant pencils, the single threads of which bear a double spathilla. The distal ends of the feet are forked or branched.
1. Gorgonetta mirabilis, n. sp. (Pl. 119, figs. 1-4).
Shell cap-shaped, flatly vaulted, or nearly hemispherical, about twice as broad as long, with smooth surface. Six ascending feet widely divergent, about twice as long as the breadth of the shell, nearly straight, arborescent, with numerous curved branches, each of which bears at the distal end a spathilla with four to six short recurved teeth (fig. 2). Six descending feet about twice as ​long as the six alternate ascending, nearly straight, covered with numerous elegant pencils. Each pencil is richly branched, with fifty to one hundred or more thread-like ramules, and each terminal ramule has two cruciate spathillæ, a larger proximal and a smaller distal (figs. 3, 4); the four recurved anchor-teeth of the proximal spathilla are twice as large as those of the distal. The distal end of each descending foot bears three or four very stout terminal branches, each of which is about as long as the shell and again trifurcate at the distal end.
Dimensions.—Length of the shell 0.2 to 0.3, breadth 0.4 to 0.5.
Habitat.—Tropical Atlantic, Stations 346 to 348, surface.
2. Gorgonetta geryonia, n. sp.
Shell hemispherical, twice as broad as long, with short scattered thorns on the surface. Twelve feet of similar shape to those in the preceding species, but differing in the following characters:—the six ascending feet are much smaller, about as long as the breadth of the shell, and each bears only six to twelve short branches; the six descending feet are about three times as long as the shell, more or less curved; their pencils much smaller, and the two spathillæ of each pencil-thread bear five anchor-teeth. The distal ends are more richly and irregularly branched.
Dimensions.—Length of the shell 0.4, breadth 0.7.
Habitat.—Indian Ocean (Cocos Islands), Rabbe, surface.
3. Gorgonetta carmarina, n. sp.
Shell flat, cap-shaped, three times as broad as long. Twelve feet similar in shape to those of the two preceding species, but more irregular in form and arrangement, and differing in the following characters:—the six ascending feet are nearly horizontally expanded, one and a half times as long as the breadth of the shell, with few short branches, each of which bears a spathilla with six recurved anchor-teeth. The six descending feet are about five times as long as the shell, irregularly curved, studded with numerous small pencils, each thread of which bears a double spathilla with six teeth. The distal ends are irregularly branched.
Dimensions.—Length of the shell 0.2, breadth 0.7.
Habitat.—South Pacific, Station 318, depth 2040 fathoms.
4. Gorgonetta bisenaria, n. sp.
Shell campanulate, similar to that of Gazelletta melusina (Pl. 118, fig. 1), with smooth surface. Six ascending feet about as long as the shell, nearly straight, similar to those of Gorgonetta mirabilis (Pl. 119, fig. 1). Six descending feet also similar to those of the latter, but shorter, about twice as long as the shell, strongly curved, studded with numerous small pencils, each thread of which has a double spathilla with three teeth. The distal end of each foot bears a whorl of six to eight irregular forked branches.
Dimensions.—Length of the shell 0.5, breadth 0.4.
Habitat.—Central Pacific, Station 263, surface.
Genus 704. Polypetta, n. gen.
Definition.—Medusettida with numerous (ten to twenty or more) articulate feet.
The genus Polypetta comprises those Medusettida in which the number of feet is very large and not limited, usually twenty to thirty or more. The few specimens of this genus that have been observed are rather different; and it may be that only the two first species described in the following lines are true Medusettida; they possess the usual distinctly alveolate feet, and are derived from the similar Medusetta or Gazelletta simply by multiplication of the feet. The two other species, however (figured in Pl. 116, figs. 1, 2, as Porospathis), belong perhaps to another family of Phæodaria (Castanellida?); their shell-structure is peculiar and their feet not distinctly alveolate; they may therefore represent a peculiar genus Porospathis (Haeckel, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, 1879, p. 5).
1. Polypetta polynema, n. sp.
Shell campanulate, thorny, about as long as broad, with slightly constricted mouth, similar to that of Gazelletta orthonema (Pl. 120, fig. 10). Shell-wall hollow, with irregular polygonal alveoles. Peristome with a corona of eighteen divergent, curved, cylindrical feet of unequal size; six larger primary on the margin of the shell, the other twelve secondary, between the former, somewhat above the margins at different heights. The feet are two to three times as long as the shell, irregularly curved and distinctly alveolate, without appendages.
Dimensions.—Length of the shell 0.12, breadth 0.11.
Habitat.—Central Pacific, Station 266, surface.
2. Polypetta alveolata, n. sp.
Shell campanulate, thorny, about as long as broad, very similar to that of Medusetta craspedota (Pl. 120, fig. 4). Shell-wall hollow, with subregular hexagonal alveoles. Peristome prolonged into a short funnel-shaped proboscis, twice as long as the similar velum of the latter. The velum is surrounded by a corona of eight larger and eight to twelve smaller feet; the larger are about as long as the shell, divergent, irregularly curved, thorny, and distinctly alveolate; the smaller feet are scattered above the latter and form an immediate transition to the small spines of the shell-surface.
Dimensions.—Length of the shell 0.08, breadth 0.09.
Habitat.—South Pacific, Station 284, surface.
​3. Polypetta tabulata, n. sp. (Pl. 116, figs. 2, 2a, 2b).
Shell subspherical, with elegantly panelled or tabulate surface, composed of small triangular plates, which are separated by a network of prominent crests; at each nodal point of the network a small conical thorn arises (figs. 2a, 2b). Each triangular plate seems to contain a hollow alveole, which opens into the shell-cavity (?). On the surface of the shell are scattered numerous (thirty to forty or more), cylindrical, hollow, radial spines, which are straight or slightly curved, not distinctly alveolate, and increase in size towards the mouth. The aboral spines are scarcely one-third as long as the radius of the shell, whilst the oral spines are three times as long as its diameter. The proboscis of the constricted mouth is a hollow cylinder, longer than the shell-radius, and armed with a corona of fifteen to twenty slender bristle-shaped teeth. The position of this singular species in this family is doubtful.
Dimensions.—Diameter of the shell 0.1 to 0.11, length of the peristome 0.07, breadth 0.02.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
4. Polypetta mammillata, n. sp. (Pl. 116, figs. 1, 1a).
Shell subspherical, densely covered with numerous mammiliform hollow papillæ, between which are scattered single longer, hollow, radial spines; these are irregularly curved, cylindrical, without distinct alveoles; the twelve longest are two to three times as long as the shell, divergent in the oral direction, and surround the base of the peristome in two irregular alternate circles, each with six spines. The hollow papillæ of the surface, between which are placed numerous circular pores (or dimples?), open into the shell-cavity by a small pore (fig. 1a); they are perhaps reduced radial spines. The constricted peristome is conical and prolonged into an inversely conical proboscis, which is about as long as the radius of the shell; its dilated mouth is surrounded by a corona of slender, divergent, bristle-shaped teeth. The position of this species in the family Medusettida is doubtful; perhaps it is more closely allied to the Castanellida.
Dimensions.—Diameter of the shell 0.12; length of the proboscis 0.08, breadth 0.03; length of the shorter spines 0.1, of the longest spines 0.3.
Habitat.—North Pacific, Station 252, surface.
Family LXXX. Castanellida, Haeckel, 1879 (Pl. 113).
Castanellida, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Phæodaria with a spherical or subspherical shell, exhibiting ordinary lattice-work, with circular or roundish pores. Radial spines without circles of basal pores. Mouth of the shell large, usually circular and armed with teeth. Central capsule excentric, placed in the aboral half of the shell-cavity.
​The family Castanellida represents a common and widely distributed group of Phæodaria, which posses a very simple and uniform shell, viz., a simple lattice-sphere with radial spines and one simple mouth. It may therefore be easily confounded with the Coscinommida, or those Sphæroidea in which the shell is also a simple lattice-sphere armed with radial spines (Astrosphærida simplicia, p. 209). Indeed the shell of both groups is very similar, and differs in one important point only; the Castanellida constantly possess one larger opening in the shell-wall, the shell-mouth, which is either smooth or armed with a corona of teeth; in the Coscinommida, however, such a mouth is never present. The living specimens of both groups, and those shells in which the soft body is preserved, are very easily distinguished, since the shell encloses in the Coscinommida the central capsule and the transparent calymma only, whilst the latter, besides, in the Castanellida contains a voluminous dark brown or green mass of phæodella, the characteristic phæodium. A closer examination of the central capsule reveals in all Castanellida the typical operculum, the astropyle, with the proboscis of the Phæodaria, which is never present in any Sphæroidea.
The Castanellida are easily distinguished also from those similar Phæodaria in which the shell is also a lattice-sphere; the lattice-work is constantly quite simple, as in the similar Coscinommida, never composed of separated tangential pieces (as in the Aulosphærida), or of porcellanous structure, with basal circles of pores (as in the Circoporida), or of diatomaceous structure (as in the Challengerida). The gigantic Orosphærida, which also in part posses a simple lattice-sphere, differ from the Castanellida in the absence of the peculiar shell-mouth.
Though the Castanellida belong to the most common Phæodaria, and though the number of individuals, floating on the surface of the tropical seas, is extraordinarily great, their variety of forms is very small; the six genera distinguished in the following system differ only in very slight characters, and the majority of the species are very similar, and often hardly distinguishable. The seven species figured in Pl. 113 exhibit the most striking differences which I could distinguish among all the species observed. The shell usually has the characteristic appearance of a chestnut, a sphere covered with very numerous short radial spines or bristles. In the majority of species a certain number of longer thin radial spines is scattered over the surface; these are usually simple, rarely branched. The mouth of the shell, corresponding to the proboscis of the central capsule, and placed in the same radius, is either a quite simple larger opening with a smooth margin (figs. 3, 5, 7) or is armed with a corona of teeth (figs. 1, 6).
The size of the shell varies between 0.2 and 0.8 mm., and is usually between 0.3 and 0.5 mm. Its form is in the majority of species a geometrical sphere; rarely it is somewhat irregular, slightly ellipsoidal (prolonged in the axis of the mouth and proboscis), or polyhedral (by conical protuberances from the bases of the radial spines). ​The ideal fundamental form of the shell, however, is constantly monaxonian, since the place of the shell-mouth and of the proboscis of the capsule (both lying in one axis of the sphere), causes a principal axis to be different from all others. The longer radial spines, quite variable in number and disposition, are never arranged regularly or symmetrically, and therefore determine no constant axes.
The lattice-work of the spherical shell offers also but slight differences. It is usually more or less irregular, with circular or subcircular pores of unequal sizes. More rarely the network is perfectly regular, with equidistant circular pores of equal size, and sometimes these are surrounded by hexagonal frames (fig. 6), as in many Sphæroidea. More rarely the pores are perfectly irregular, roundish or sometimes polygonal, of unequal sizes and dissimilar forms (fig. 2). The size of the pores is very variable between 0.01 and 0.05, usually between 0.015 and 0.025. They are commonly somewhat broader than the bars between them, more rarely smaller. The substance of the shell-wall is in the the majority of Castanellida hyaline, transparent (as in the similar Sphæroidea); in some larger forms, however, a network of fine axial filaments is visible in the lattice (fig. 2), and sometimes this seems to be hollow, with an axial canal (as in the large Orosphærida). Such an axial filament or fine axial canal is usually visible in the larger radial spines. The shell-wall of the Castanellida, however, never exhibits that characteristic structure (with tangential needles in a cement-like fundamental substance), which we find in all Circoporida. The latter differ also in the constant presence of circles of large pores around the bases of the radial spines, which are never found in the Castanellida. The shell becomes usually stained more or less purple by carmine, and when burned by fire, becomes of a brown colour.
The inner surface of the shell is always quite smooth, the outer surface armed with numerous short and thin radial bristles. Sometimes these bristles or "by-spines" are very short, but never perfectly wanting. Usually their length is about one-third or one-fourth of the radius of the shell, often less, rarely more. They arise from the nodal points between every three or four neighbouring spines, and are commonly very thin and straight, pointed, with slightly thickened conical basis. Rarely they are directed not quite radially, but more or less obliquely.
The larger radial spines, which arise between the thin bristles or "by-spines" and may be opposed to the latter as "main-spines," are wanting in two genera only, in Castanarium and Castanella (Pl. 113, fig. 6). They are simple in Castanidium (figs. 2, 5, 7) and Castanissa (fig. 1), irregularly branched in Castanopsis and Castanura (figs. 3, 4). Their number and disposition is never regular nor symmetrical (as in the majority of Sphæroidea) and varies even in each single species. In general the number of main-spines varies between ten and forty (rarely less or more) usually between twenty and thirty. Their length is commonly about equal to the diameter of the shell, often somewhat shorter, rarely considerably longer. Their ​thickness is in the majority of species about equal to the diameter of one or two pores of the lattice. Sometimes they are much stronger, rarely thinner.
The form of the radial main-spines is not very variable, usually it is cylindrical or cylindro-conical, rarely angular, prismatic or pyramidal. Sometimes they are straight (perfectly radial), at other times more or less irregularly curved. Usually they are simple, rarely branched; the branches are always very irregular and exhibit a remarkable tendency to unite by concrescence (figs. 3, 4). Some thicker forms of spines exhibit a remarkable structure, the surface being covered with small dimples and spinules between them (fig. 1); sometimes the dimples are hexagonal (fig. 5a). In the axis of the thicker spines there is often visible the same axial filament or funicle which we find in many other Phæodaria, more rarely a hollow axial canal.
The mouth of the shell is usually circular, more rarely polygonal or irregularly roundish (fig. 2). It is either quite smooth (fig. 3, 5, 7) or armed with a corona of strong teeth (figs. 1, 4, 6). These teeth are different from the other spines of the shell; they are much thicker than the radial bristles, and shorter than the main-spines. Their number varies between three and twenty, usually between five and seven. They are usually parallel to the main axis, which is determined by the excentric position of the mouth and the centre of the sphere (figs. 1, 6). The teeth are usually conical, more or less irregular in size and form, more rarely of equal size. The corona of teeth is usually sharply separated from the surrounding lattice-work of the shell, but has no influence on its regular spherical form.
The central capsule of the Castanellida immediately determines beyond doubt their true Phæodarian nature; it lies excentrically in the cavity of the enclosing shell, and is surrounded at the oral pole by the large and dark phæodium. The latter covers the radiate operculum of the capsule membrane and the tubular proboscis, which arises from it and is directed towards the shell mouth. Usually the diameter of the spherical central capsule is about one-third of the shell diameter, rarely one-quarter only, and in a few cases it attains nearly its half. The calymma, therefore, is larger than the capsule, and fills up the whole cavity of the shell which is not occupied by the latter. The greater part of the calymma again is filled up by the dark green or brown, sometimes black phæodella, the roundish granules which compose the voluminous non-transparent phæodium. Sometimes the latter proceeds through the mouth and is partially placed outside the shell (fig. 5).
The astropyle, or the main-opening of the central capsule, is placed on the oral pole of its main axis, while its radiate operculum and the tubular proboscis arising from it possess the same structure as in the other Phæodaria. But the two lateral parapylæ or accessory openings which are present in the majority of the latter seem to be absent in the Castanellida as well as in the Medusettida and the Challengerida. I could never observe a trace of them. The proboscis is a small cylindrical tube and is directed towards the ​mouth of the shell, therefore placed in its main axis; it is usually quite hidden in the dark phæodium, which occupies the oral half of the shell-cavity, whilst the capsule lies in the aboral half. The large nucleus of the central capsule and its double membrane present the same characters as in the other Phæodaria.
Synopsis of the Genera of Castanellida.
| No long radial main-spines (in addition to the constant short bristles of the shell-surface). | No long radial main-spines (in addition to the constant short bristles of the shell-surface). | No long radial main-spines (in addition to the constant short bristles of the shell-surface). | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth smooth, | 705. Castanarium. |
| No long radial main-spines (in addition to the constant short bristles of the shell-surface). | No long radial main-spines (in addition to the constant short bristles of the shell-surface). | No long radial main-spines (in addition to the constant short bristles of the shell-surface). | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth dentate, | 706. Castanella. |
| Long radial main-spines scattered between the short constant bristles of the shell-surface. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$ | Main spines simple. | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth smooth, | 707. Castanidium. |
| Long radial main-spines scattered between the short constant bristles of the shell-surface. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$ | Main spines simple. | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth dentate, | 708. Castanissa. |
| Long radial main-spines scattered between the short constant bristles of the shell-surface. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$ | Main spines branched. | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth smooth, | 709. Castanopsis. |
| Long radial main-spines scattered between the short constant bristles of the shell-surface. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$ | Main spines branched. | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Mouth dentate, | 710. Castanura. |
Genus 705. Castanarium, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida without radial main-spines, with a smooth mouth.
The genus Castanarium is the simplest form of all the Castanellida, and may be regarded as the common ancestral form of this family. The simple spherical shell has a smooth, toothless mouth and no larger radial spines; it is densely studded with the simple, radial bristles, which are common to all Castanellida. The shell therefore is very similar to those species of the Astrosphæride Acanthosphæra, which represent the subgenus Rhapidococcus (compare above, p. 210, Pl. 26, fig. 3); it differs from the latter in the possession of the shell-mouth, which is absent in all Sphæroidea.
1. Castanarium darwini, n. sp.
Pores regular, circular, hexagonally framed, three times as broad as the bars. Radial bristles half as long as the radius.
Dimensions.—Diameter of the shell 0.3 to 0.4, of the pores 0.03.
Habitat.—South Atlantic (east of Patagonia), Station 318, depth 2040 fathoms.
​2. Castanarium hookeri, n. sp.
Pores regular, circular, hexagonally framed, twice as broad as the bars. Radial bristles one-third as long as the radius.
Dimensions.—Diameter of the shell 0.55, of the pores 0.025.
Habitat.—Indian Ocean, Cocos Islands (Rabbe), surface.
3. Castanarium lyelli, n. sp.
Pores regular, circular, without hexagonal frames, of the same breadth as the bars. Radial bristles twice as long as the diameter of one pore.
Dimensions.—Diameter of the shell 0.24, of the pores 0.015.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
4. Castanarium lubbocki, n. sp.
Pores irregularly roundish, about of the same breadth as the roundish, non-crested bars. Radial bristles one-third as long as the radius.
Dimensions.—Diameter of the shell 0.36, of the pores 0.01 to 0.02.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
5. Castanarium huxleyi, n. sp.
Pores irregularly polygonal, two to three times as broad as the bars, separated by prominent polygonal crests. Radial bristles half as long as the radius.
Dimensions.—Diameter of the shell 0.45, of the pores 0.02 to 0.05.
Habitat.—South Pacific (off Australia), Station 165, surface.
Genus 706. Castanella, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida without radial main-spines, with a dentate mouth.
The genus Castanella comprises the most common and most widely distributed species of Castanellida. It agrees in general shape with its ancestral form, the preceding Castanarium, differing from it only in the possession of strong teeth, which form a corona around the mouth.
​1. Castanella wyvillei, n. sp. (Pl. 113, fig. 6).
Pores regular, circular, of equal size, hexagonally framed, of the same breadth as the bars. Radial bristles twice as long as the diameter of one pore. Mouth with five to six parallel, conical strong teeth, which are twice as long as a bristle (fig. 6a).
Dimensions.—Diameter of the shell 0.5 to 0.7, of the pores 0.02 to 0.03.
Habitat.—North Pacific, Stations 252 to 256, surface.
2. Castanella thomsoni, n. sp.
Pores regular, circular, of equal size, hexagonally framed, twice as broad as the bars. Radial bristles about as long as the diameter of one pore. Mouth with four strong, conical teeth, forming a regular cross, four times as long as a bristle.
Dimensions.—Diameter of the shell 0.7 to 0.8, of the pores 0.03.
Habitat.—South Pacific, Stations 295 to 298, surface.
3. Castanella campbelli, n. sp.
Pores regular, circular, hexagonally framed, three times as broad as the bars. Radial bristles half as long as the radius of the shell. Mouth with a coronet of eight conical, parallel teeth, of the same length as the bristles, but four to six times as thick.
Dimensions.—Diameter of the shell 0.4 to 0.45, of the pores 0.025.
Habitat.—Central Pacific, Stations 270 to 274, surface.
4. Castanella sloggetti, n. sp.
Pores subregular, circular, without frames, of different sizes, about twice as broad as the bars. Radial bristles three times as long as one pore. Mouth with five or six strong, conical teeth, twice as long as the bristles.
Dimensions.—Diameter of the shell 0.3 to 0.36, of the pores 0.02 to 0.03.
Habitat.—Tropical Atlantic, Stations 347 to 349, surface.
5. Castanella balfouri, n. sp.
Pores irregular, roundish, two to three times as broad as the bars. Bristles about one-fourth as long as the radius. Mouth with four strong conical teeth, forming a cross, somewhat longer and much thicker than the bristles.
Dimensions.—Diameter of the shell 0.22 to 0.28, of the pores 0.01 to 0.02.
Habitat.—North Pacific, Stations 240 to 245, surface.
​6. Castanella channeri, n. sp.
Pores irregular, roundish, two to four times as broad as the bars. Bristles nearly half as long as the radius. Mouth with seven to nine short conical teeth, shorter than the bristles, but much thicker.
Dimensions.—Diameter of the shell 0.3 to 0.4, of the pores 0.02 to 0.025.
Habitat.—North Atlantic, Stations 352 to 354, surface.
7. Castanella horstoni, n. sp.
Pores irregular, polygonal, three to four times as broad as the bars. Bristles about as long as the radius. Mouth with six stout pyramidal teeth, which are scarcely one-third as long as the radius.
Dimensions.—Diameter of the shell 0.55, of the pores 0.02 to 0.025.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
Genus 707. Castanidium, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida, with simple radial main-spines and a simple smooth mouth.
The genus Castanidium agrees with its ancestral form Castanarium in the simple shape of the smooth and toothless mouth, but differs from it in the possession of long radial main-spines, which are scattered between the constant radial bristles or by-spines of the surface. The shell agrees therefore in its general shape with the Astrosphæride Heliosphæra, as defined above (p. 217, Pl. 26, fig. 9), but differs from it in the possession of the shell-mouth wanting in all Sphæroidea.
1. Castanidium willemoesi, n. sp.
Pores regular, circular, hexagonally framed, twice as broad as the bars. Bristles three times as long as the diameter of one pore. Radial main-spines straight, conical, smooth, as long as the radius.
Dimensions.—Diameter of the shell 0.3 to 0.4, of the pores 0.012 to 0.016.
Habitat.—Central Pacific, Station 263 to 274, surface.
2. Castanidium wildi, n. sp.
Pores regular, circular, hexagonally framed, of the same breadth as the bars. Bristles twice as long as one pore. Radial main-spines straight and short, cylindrical, with dimpled surface (as in Pl. 113, fig. 1), as broad as one pore and as long as the diameter of the shell.
Dimensions.—Diameter of the shell 0.66, of the pores 0.045.
Habitat.—South Pacific, Station 297, surface.
​3. Castanidium buchanani, n. sp. (Pl. 113, fig. 7).
Pores regular, circular, without frames, twice as broad as the bars, of variable size. Bristles five to six times as long as one pore. Radial main-spines numerous, straight, slender, cylindrical, about as long as the diameter of the shell.
Dimensions.—Diameter of the shell 0.25 to 0.3, of the pores 0.012 to 0.02.
Habitat.—Tropical Atlantic, Stations 346 to 349, surface.
4. Castanidium murrayi, n. sp. (Pl. 113, figs. 5, 5a).
Pores subregular, circular, without frames, three times as broad as the bars. Bristles three times as long as one pore. Radial main-spines cylindrical, stout, irregularly curved, longer than the shell-diameter, covered with longish hexagonal dimples, which are separated by a network of prominent crests (fig. 5a).
Dimensions.—Diameter of the shell 0.4 to 0.5, of the pores 0.02 to 0.025.
Habitat.—North Atlantic, Station 352 to 354, surface.
5. Castanidium aldrichi, n. sp.
Pores subregular, circular, without frames, of variable size, about as broad as the bars. Bristles four times as long as one pore. Radial main-spines conico-cylindrical, irregularly curved, straight, about as long as the radius. (The conical base of the spines is inflated and fenestrated, therefore the shell is nearly polyhedral.)
Dimensions.—Diameter of the shell 0.35 to 0.4, of the pores 0.012 to 0.015.
Habitat.—Central Pacific, Stations 270 to 274, surface.
6. Castanidium bromleyi, n. sp.
Pores irregular, roundish, two to four times as broad as the bars. Bristles half as long as the radius. Radial main-spines cylindrical, straight, slender, longer than the shell-diameter.
Dimensions.—Diameter of the shell 0.22 to 0.26, of the pores 0.006 to 0.02.
Habitat.—Indian Ocean and Southern Pacific, Stations 162 to 169, surface.
7. Castanidium bethelli, n. sp.
Pores irregular, roundish or polygonal, two to three times as broad as the bars. Bristles one-third as long as the radius. Radial main-spines conico-cylindrical, irregularly curved, with dimpled surface, somewhat longer than the radius.
Dimensions.—Diameter of the shell 0.5 to 0.6, of the pores 0.015 to 0.03.
Habitat.—North Pacific, Stations 235 to 245, surface.
​8. Castanidium moseleyi, n. sp. (Pl. 113, fig. 2).
Pores irregular, roundish or polygonal, two to four times as broad as the bars. Bristles about as long as the diameter of one pore, or a little longer. Radial main-spines cylindrical, irregularly curved, somewhat longer than the diameter of the shell; their base is more or less inflated and fenestrated, therefore the shell is nearly polyhedral.
Dimensions.—Diameter of the shell 0.7 to 0.8, of the pores 0.01 to 0.04.
Habitat.—Tropical Atlantic, Stations 346 to 349, surface.
Genus 708. Castanissa, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida with simple radial main-spines and a dentate mouth.
The genus Castanissa agrees with the preceding Castanidium in the possession of large radial main-spines, scattered between the numerous bristles or by-spines of the surface; but it differs from it in the possession of teeth around the mouth, identical with those of Castanella; it may be derived therefore either from the latter by development of main-spines, or from the former by formation of teeth.
1. Castanissa challengeri, n. sp. (Pl. 113, fig. 1).
Pores regular, circular, three times as broad as the bars. Bristles one-fourth as long as the radius. Radial main-spines (about twelve) very stout, straight, cylindrical, at the distal end conical, pointed, with dimpled surface, about half as long as the radius. Mouth very large, circular, about one-third as broad as the shell, with a corona of twelve to sixteen very large, triangular, parallel teeth.
Dimensions.—Diameter of the shell 0.7 to 0.8, of the pores 0.03.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
2. Castanissa pearceyi, n. sp.
Pores regular, circular, twice as broad as the bars. Bristles half as long as the radius. Radial main-spines (about twenty) slender, cylindrical, smooth, irregularly curved, about as long as the radius. Mouth large, half as broad as the radius, with a corona of ten to twelve irregular, slender teeth.
Dimensions.—Diameter of the shell 0.5 to 0.6, of the pores 0.02.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
​3. Castanissa richardsi, n. sp.
Pores subregular, circular, about as broad as the bars. Bristles twice as long as one pore. Radial main-spines (about twenty) slender, cylindrical, irregularly curved, with dimpled surface (like those in Pl. 113, fig. 5a). Mouth with a corona of six stout, parallel, triangular teeth.
Dimensions.—Diameter of the shell 0.3 to 0.35, of the pores 0.015.
Habitat.—North Atlantic, Station 354, surface.
4. Castanissa crosbiei, n. sp.
Pores irregular, roundish, two to three times as broad as the bars. Bristles one-third as long as the radius. Radial main-spines very numerous, straight, cylindrical, smooth, about as long as the diameter of the shell. Mouth with ten or twelve irregular, conical, parallel teeth.
Dimensions.—Diameter of the shell 0.28, of the pores 0.01 to 0.015.
Habitat.—North Pacific, Stations 231 to 235, surface.
5. Castanissa macleani, n. sp.
Pores irregular, roundish or polygonal, two to four times as broad as the bars. Bristles about one-fourth as long as the radius. Radial main-spines numerous, straight, conical, stout, with dimpled surface, shorter than the radius. Mouth with six to eight irregular conical teeth.
Dimensions.—Diameter of the shell 0.32, of the pores 0.012 to 0.024.
Habitat.—Tropical Pacific, Station 268, depth 2900 fathoms.
6. Castanissa hoylei, n. sp.
Pores irregular, polygonal, two to three times as broad as the bars. Bristles nearly half as long as the radius. Radial main-spines (about thirty) very long and thin, cylindrical, irregularly curved, at the conical base inflated and fenestrated; shell therefore slightly polyhedral. Mouth with five strong conical teeth.
Dimensions.—Diameter of the shell 0.35 to 0.4, of the pores 0.02 to 0.03.
Habitat.—North Pacific, Station 245 to 250, surface.
Genus 709. Castanopsis, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida with branched radial main-spines and a simple smooth mouth.
The genus Castanopsis differs from its ancestral form Castanidium in the ramification of the radial main-spines; the branches are usually very irregular and often partly ​confluent. The shell is very similar to the Astrosphæride Cladococcus (compare above p. 223, Pl. 27), but differs from it in the possession of the shell-mouth, absent in all Sphæroidea.
1. Castanopsis naresi, n. sp. (Pl. 113, fig. 3).
Pores subregular, circular, about twice as broad as the bars. Bristles twice as long as one pore. Radial main-spines somewhat shorter than the diameter of the shell, straight, cylindrical, in the proximal half simple, in the distal half irregularly branched, each with ten to twelve partly confluent branches.
Dimensions.—Diameter of the shell 0.6 to 0.7, of the pores 0.02 to 0.03.
Habitat.—Tropical Atlantic, Station 347 to 349, surface.
2. Castanopsis macleari, n. sp.
Pores irregular, roundish, two to four times as broad as bars. Bristles half as long as the radius. Radial main-spines about as long as the radius, stout and straight, cylindrical, forked at the distal end, with two or three unequal fork-branches.
Dimensions.—Diameter of the shell 0.42, of the pores 0.015 to 0.03.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
3. Castanopsis fergusoni, n. sp.
Pores irregular, roundish or polygonal, about as broad as the bars. Bristles three times as long as one pore. Radial main-spines somewhat longer than the diameter of the shell, cylindrical, with irregular and partly confluent lateral branches (similar to Pl. 113, fig. 4a).
Dimensions.—Diameter of the shell 0.55, of the pores 0.012 to 0.016.
Habitat.—North Atlantic, Station 354, surface.
Genus 710. Castanura, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Castanellida with branched radial main-spines and a dentate mouth.
The genus Castanura differs from the preceding Castanopsis in the possession of a corona of teeth surrounding the mouth, similar to that of Castanissa. It differs from the latter in the ramification of the radial main-spines, wherein it agrees with the former. Castanura may therefore be derived either from Castanissa by ramification of the main-spines, or from Castanopsis by development of teeth around the mouth.
​1. Castanura tizardi, n. sp. (Pl. 113, fig. 4, 4a).
Pores regular, circular, without hexagonal frames, twice as broad as the bars. Bristles twice as long as one pore. Radial main-spines somewhat longer than the radius, straight, very stout, with irregular lateral branches, which are partly confluent. Mouth with six strong conical teeth.
Dimensions.—Diameter of the shell 0.6, of the pores 0.03.
Habitat.—Tropical Atlantic, Station 346, surface.
2. Castanura havergali, n. sp.
Pores regular, circular, hexagonally framed, as broad as the bars. Bristles three times as long as one pore. Radial main-spines as long as the shell-diameter, in the basal half simple, in the distal half with irregular, not confluent, lateral branches. Mouth with ten to twelve irregular, parallel, conical teeth of different sizes.
Dimensions.—Diameter of the shell 0.5, of the pores 0.045.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
3. Castanura swirei, n. sp.
Pores regular, circular, hexagonally framed, as broad as the bars. Bristles half as long as the radius. Radial main-spines straight, longer than the shell-diameter; on the distal end with a few irregular, confluent, lateral branches. Mouth with six larger and six alternate smaller, parallel, conical teeth.
Dimensions.—Diameter of the shell 0.28, of the pores 0.015.
Habitat.—North Pacific, Station 253, surface.
4. Castanura carpenteri, n. sp.
Pores irregular, roundish, twice to four times as broad as the bars. Bristles about as long as the largest pores. Radial main-spines irregularly curved, longer than the shell-diameter, with inflated and fenestrated conical base; in the distal half irregularly branched, with simple, not confluent, lateral branches. Mouth with six to nine irregular, strong, conical teeth.
Dimensions.—Diameter of the shell 0.3, of the pores 0.012 to 0.025.
Habitat.—South Atlantic, Station 331, depth 1715 fathoms.
Family LXXXI. Circoporida, Haeckel, 1879 (Pls. 114-117).
Circoporida, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Phæodaria with a spherical or polyhedral shell, exhibiting a peculiar solid porcellanous structure, with a stellate circle of radial pores around the base of the hollow radial spines. Mouth usually with teeth. Surface of the shell ​tabulate, panelled or dimpled. Central capsule excentric, placed in the aboral half of the shell-cavity.
The family Circoporida comprises those Phæodaria in which the simple spherical or polyhedral shell exhibits a peculiar porcellanous structure, possesses a simple mouth, and is particularly distinguished by the constant character denoted by their name, viz., by circles of pores surrounding the base of the radial spines. It agrees in these striking peculiarities with the following family, the Tuscarorida, but differs from them essentially by the spherical or polyhedral form of the shell, which is never ovate, with the main axis prolonged. The radial spines, variable in number, are regularly or symmetrically disposed in all Circoporida, whilst they are arranged around the poles of the main axis in all Tuscarorida. Whilst the latter are always extremely large, more than a millimeter in size, the former are much smaller and never reach the diameter of a millimeter. The number of genera and species in this family is not large, and the majority are very rare, but they belong to the most remarkable Radiolaria by the peculiar structure, as well as by the geometrical regularity of the polyhedral shell.
The Circoporida may be divided into two different subfamilies, the Circogonida and the Haeckelinida. The latter are represented by the single genus Haeckeliana (Pl. 114), and possess a spherical shell with numerous small dimples between the circles of pores, and numerous simple radial spines which do not exhibit a regular arrangement. The Circogonida, on the other hand, comprise all other genera (Pls. 115-117) and possess a panelled shell with polygonal plates, and a certain number of radial spines, which are regularly disposed on the corners of the polyhedral shell, and usually armed with verticillate bristles and terminal forks or spathillæ. Perhaps the Circogonida and Haeckelinida may be better considered as two separate families.
The geometrical fundamental form of the shell is in the Circoporida of the highest interest, since it exhibits regular proportions, which are very rare in other organic forms, generally some rare forms of regular polyhedrons. The shell in all members of this family belongs to that group of geometrical forms which I have called in my General Morphology "Polyaxonia" (vol. i., 1866, pp. 406-416). The shell therefore is constantly an "endospherical polyhedron," i.e., a polyhedron, all the corners of which lie in a spherical surface. The corners are always indicated by the bases of the radial spines arising from the surface of the shell and marking its axes, and it is immaterial whether the shell itself is a true polyhedron or a sphere; for in the latter case also the radial spines mark the axes of the polyhedron.
The six genera which we here distinguish among the Circoporida, represent six different fundamental forms. Circoporus (Pl. 115, figs. 1-3; Pl. 117, figs. 5, 6) possesses six radial spines, opposite in pairs in three diameters, perpendicular one to another; it agrees therefore with the Cubosphærida (p. 169, Pls. 21-25) and ​represents the regular octahedron, with eight congruent triangular faces and six corners. It has the same form as the well-known antheridia of Chara (Gener. Morphol., vol. i. p. 412). Circogonia (Pl. 115, figs. 8-10; Pl. 117, fig. 1) exhibits twelve radial spines, opposite in pairs in six equidistant diameters. The surface of the shell is divided into twenty equal and equilateral triangles, and agrees therefore with the regular icosahedron. The same form appears also in some forms of Aulosphæra, and in several Astrosphærida (Gener. Morphol., vol. i. p. 411). Circorrhegma (Pl. 117, fig. 2) possesses a regular shell with twelve equal pentagonal faces and twenty equidistant corners, from which arise twenty regularly disposed radial spines. It represents therefore the regular "pentagonal dodecahedron," the same remarkable form which is found in some Astrosphærida, and in the pollen-grains of some plants, e.g., Bucholzia maritima, Fumaria spicata, Polygonum amphibium, &c. (Gener. Morphol., vol. i. p. 412, Taf. ii. fig. 18).
The three genera of Circoporida mentioned therefore represent three different forms of regular polyhedrons, in the exact mathematical sense, viz., Circoporus, the regular octahedron, Circogonia, the regular icosahedron, and Circorrhegma, the regular dodecahedron. In each of these three regular forms all the faces, edges, and corners are equal. The remaining three genera of Circoporida represent, however, three forms of subregular or irregular endospherical polyhedra, which are not perfectly regular. Circospathis (Pl. 115, figs. 4-7; Pl. 117, fig. 3) is a rather common form, and constantly possesses nine symmetrically disposed radial spines; the shell is either spherical or polyhedral, with fourteen triangular faces and thirty edges; the nine spines lie in three meridional planes, which are crossed at equal angles (three equidistant spines in each plane). We call this remarkable form the tetradecahedron; it appears also in some Astrosphærida (e.g., in Haliomma echinaster, figured in my Monograph, Taf. xxiv. fig. 1). Circostephanus (Pl. 116, fig. 3) exhibits a subregular polyhedral shell with a variable number of triangular faces and of radial spines (twenty-four to forty or more). Circostephanus sexagenarius possesses sixty triangular equilateral faces, which are disposed in twelve pentagonal groups (each with five faces), so that the shell seems to be derived from a regular pentagonal dodecahedron, the twelve regular faces of which are divided each into five congruent triangles. From its corners arise thirty-two radial spines (twelve from the central points of the pentagons, twenty from the meeting corners of every three pentagons). In other cases the number of faces and radial spines seems to be larger and their arrangement more irregular. The same may be said of Haeckeliana, in which the dimpled shell is constantly spherical, and possesses a variable number of radial spines, from sixteen to fifty-five (usually between thirty and forty).
The structure of the shell in the Circoporida is the same as in the Tuscarorida, of a peculiar porcellanous nature. The shell-wall is very thick, more or less opaque, and in direct light whitish or yellowish. Its surface is dimpled, with numerous small, circular, ​roundish or polygonal dimples in Haeckeliana (Pl. 114, figs. 1-6). In the Circogonida, however, the surface is panelled, with regular or irregular polygonal plates, often separated by high prominent crests (Pl. 115, figs. 4-9, &c.). Numerous simple thin needles of silica lie tangentially disposed and irregularly scattered in the porcellanous or cement-like substance of the thick shell-wall. Under a strong lens this substance appears finely punctate, being probably pierced by numerous very fine pores. The surface of the shell is therefore minutely roughened, and often appears quite black under the microscope, by the adhesion of innumerable fine air-bubbles. In all Circoporida, as well is in the Tuscarorida, the porcellanous shell has not the perfect transparency of the purely siliceous shells of other Radiolaria; its refractive power is somewhat different from the latter; it becomes deeply stained by carmine and browned by fire, and seems therefore to consist of a peculiar carbonic silicate.
The shell in all Circoporida exhibits a simple, excentric mouth, which corresponds to the main osculum of the central capsule. The excentric position of this shell-mouth has no influence on the regular form of the shell. The mouth is either circular or polygonal, usually about as large as a basal circle of pores. It is always armed with prominent conical or pyramidal teeth, the number of which is variable and seems to depend partly upon the number of the shell-faces or the radial spines. Circoporus has usually four cruciate teeth (Pl. 115, fig. 1; Pl. 117, figs. 4, 5). Circorrhegma exhibits a pentagonal mouth with five teeth (Pl. 117, fig. 2). Circogonia possesses a hexagonal mouth with six teeth (Pl. 115, fig. 8; Pl. 117, fig. 1). Circospathis has no constant number; some species have five teeth (Pl. 115, fig. 4), others four (Pl. 115, fig. 10), others nine (Pl. 117, fig. 3a). Circostephanus is also variable; one species exhibits eight teeth (Pl. 116, fig. 3a), another ten, another twelve. In Haeckeliana (Pl. 114, fig. 3) the teeth are smaller and more numerous. Usually the teeth arise vertically from the surface of the shell and are spinulate; more rarely their points are directed towards the centre of the mouth. Sometimes numerous thin needles arise between the teeth (Pl. 115, fig. 10).
The radial spines of the Circoporida are tubular, usually cylindrical and conical at the thickened base, more rarely prismatic or slenderly pyramidal, with three or more edges; sometimes the edges are spirally wound around the axis (Pl. 115, fig. 6). In the majority of species their length is about equal to the diameter of the shell; often they are somewhat shorter, more rarely longer. Their tubular structure is always the same as in the Tuscarorida; the wall of the tube is thick, and in the axis of its cavity lies an axial cord or funicle, which is connected with the wall by numerous horizontal, simple, or branched threads (Pl. 115, figs. 6, 7). The axial funicle itself is either a simple thread of silica, or a strand, composed of three to fifteen or more filaments, which are closely twisted like a rope around the axis of the spine, and arise separately from the bridges between the pores of the basal circle (Pl. 115, figs. 7, 9). The number of ​pores in these circles is very variable, commonly from three to nine, sometimes twelve to fifteen or more; their form is usually irregularly ovate (Pl. 115, figs. 7, 9). The bridges between the pores usually bear numerous siliceous threads or bristles, which are curved downwards or upwards (Pl. 115, figs. 4-6). Sometimes the spines are entirely covered with similar bristles or cilia (Pl. 117, figs. 2-5), more rarely with regular verticils of lateral branches (Pl. 117, fig. 6).
The distal ends of the radial spines are simple in Haeckeliana (Pl. 114), whilst in the other Circoporida they are usually (or perhaps constantly) either forked or armed with a verticil of terminal branches. When the spines are simply forked, their two terminal branches lie in certain meridional planes (Pl. 117, fig. 5). The same is probably the case when they bear three divergent branches (Pl. 115, figs. 1, 2), or four crossed branches (Pl. 117, figs. 4, 6). The larger species usually bear a corona of five curved branches disposed around the distal apex of each spine (Pl. 116, fig. 3; Pl. 117, figs. 1, 2). Sometimes the formation of these coronas is twice or more often repeated, so that the spines appear verticillate.
The central capsule of the Circoporida (Pl. 115, fig. 8; Pl. 117, fig. 6) is usually about half as large as the enclosing shell, and lies excentrically in that half of its cavity which is remote from the shell-mouth (Pl. 115, fig. 8). The other half (near the mouth) is filled up by the cap-shaped, dark phæodium. The proboscis, or the central tubule of the astropyle, is hidden in the axis of the blackish phæodium, and is directed towards the mouth of the shell; it is often S-shaped, more or less curved. The circular radiate operculum of the astropyle, placed on the base of the proboscis, exhibits numerous branched radial ribs, and closes the main-opening like the lid of a tea-kettle (Pl. 115, fig. 3). The number of the parapylæ, or the accessory openings of the capsule, which in the majority of Phæodaria is two, seems to be usually increased in the Circoporida. In Circoporus the capsule seems to posses six and in Circospathis nine secondary openings, and therefore there is some probability that each circle of pores on the base of a radial spine corresponds to a secondary opening of the capsule. In Haeckeliana, however (Pl. 114), I could observe no parapylæ at all. These accessory openings are always very small in the Circoporida, and may be easily overlooked. Furthermore, the number of observations respecting this difficult point is too small, and their certainty not satisfactory; it requires therefore further accurate examination, as also does the whole central capsule of the Circoporida.
The numerous and remarkable characters of shape and structure, which we have described above as occurring in the Circoporida, are also found in the following closely allied family, the Tuscarorida; all the species are inhabitants of great depths. Perhaps it may therefore be more convenient to separate these two families from the other Phæogromia as a peculiar order, under the name Phæocalpia.
Synopsis of the Genera of Circoporida.
| I. Subfamily Circogonida. Shell spherical or polyhedral with panelled structure and polygonal plates. A certain number of radial spines are geometrically disposed. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell octahedral (or spherical), | | Six radial spines, | 711. Circoporus. |
| I. Subfamily Circogonida. Shell spherical or polyhedral with panelled structure and polygonal plates. A certain number of radial spines are geometrically disposed. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell tetradecahedral, | | Nine radial spines, | 712. Circospathis. |
| I. Subfamily Circogonida. Shell spherical or polyhedral with panelled structure and polygonal plates. A certain number of radial spines are geometrically disposed. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell icosahedral, | | Twelve radial spines, | 713. Circogonia. |
| I. Subfamily Circogonida. Shell spherical or polyhedral with panelled structure and polygonal plates. A certain number of radial spines are geometrically disposed. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell dodecahedral, | | Twenty radial spines, | 714. Circorrhegma. |
| I. Subfamily Circogonida. Shell spherical or polyhedral with panelled structure and polygonal plates. A certain number of radial spines are geometrically disposed. | $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$ | Shell polyhedral, | | Twenty-four to forty or more radial spines, | 715. Circostephanus. |
| II. Subfamily Haeckelinida. | $\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ | Shell spherical, with dimpled structure, and a variable number of radial spines (without polygonal plates), | Shell spherical, with dimpled structure, and a variable number of radial spines (without polygonal plates), | Shell spherical, with dimpled structure, and a variable number of radial spines (without polygonal plates), | 716. Haeckeliana. |
Subfamily 1. Circogonida, Haeckel.
Definition.—Circoporida with panelled shell, composed of polygonal plates. The shell is usually polyhedral, more rarely spherical, and the radial spines are usually (or perhaps constantly) branched and regularly arranged.
Genus 711. Circoporus, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Circoporida with a spherical or regularly octahedral shell, composed of eight congruent, triangular plates, with six corners from which arise six radial spines, opposite in pairs in three diameters, perpendicular one to another.
The genus Circoporus, the simplest among the Circoporida, is distinguished by the regular octahedral form of the shell, with the three equal axes of the regular crystalline system perpendicular one to another. Six equal radial spines, arising from the six corners, lie opposite in pairs in those three dimensive axes. The eight equal triangular faces of the octahedron are sometimes plane, sometimes concave or convex, and sometimes the shell becomes spherical. In this case it becomes very similar to the Hexastylida among the Sphæroidea.
1. Circoporus sexfurcus, Haeckel (Pl. 117, fig. 5).
Shell spherical, covered with irregular, polygonal plates. Six radial spines shorter than the diameter of the shell, covered with thin curved bristles, in the proximal half cylindrical, in the distal half forked, each with two equal curved fork-branches. Around the ciliated base of each spine a ​corona of twelve to sixteen pores surrounded by a circle of numerous, curved, longer bristles. Mouth cruciform, with four triangular, convergent teeth.
Dimensions.—Diameter of the shell 0.55, length of the spines 0.4.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
2. Circoporus hexastylus, n. sp. (Pl. 117, fig. 4).
Shell regularly octahedral, with eight plane, congruent, triangular faces, which are covered with a very delicate network of small, regular, hexagonal plates. Six radial spines as long as the radius of the shell, four-sided pyramidal, simple, in the basal half covered with numerous curved bristles. Around the base of each spine a corona of four equal pores, surrounded by a circle of twelve short teeth. Apex with four crossed, curved branches (like those of Circospathis tetrodon). Mouth cruciform, with four smooth teeth.
Dimensions.—Diameter of the shell 0.24, length of the spines 0.12.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
3. Circoporus characeus, n. sp.
Shell spherical, covered with a delicate network of irregular polygonal plates. Six radial spines longer than the diameter of the shell, cylindrical, covered with numerous curved bristles, each with eight pores at the base surrounded by a circle of long bristles. Apex of each spine with a trident or fuscina, similar to that of the following species. Similar to an antheridium of Chara.
Dimensions.—Diameter of the shell 0.32, length of the spines 0.4.
Habitat.—South Pacific, Station 285, depth 2375 fathoms.
4. Circoporus sexfuscinus, n. sp. (Pl. 115, figs. 1-3).
Shell subregular, octahedral, with eight triangular, concave, somewhat unequal faces, which are covered with an extremely delicate network of small square dimples, and furrowed by radial crests arising from the bases of the spines (fig. 2). Six radial spines about as long as the diameter of the shell, four-sided, prismatic, with rounded edges; each in the basal half with a verticil of four crossed, curved bristles (fig. 1), sometimes with two verticils (fig. 2); on the distal apex inflated, armed with a trident or fuscina. Around the base of each spine four crossed elliptical pores. Mouth cruciform, with four small teeth (fig. 1).
Dimensions.—Diameter of the shell 0.2 to 0.25, length of the spines 0.2 to 0.25.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
5. Circoporus octahedrus, n. sp. (Pl. 117, fig. 6).
Shell regularly octahedral, with eight plane, or slightly convex, congruent, triangular faces, which are covered with very small, regular, triangular plates (like those of Polypetta tabulata, Pl. 116, fig. 2). Six stout radial spines, about as long as the diameter of the shell, four-sided prismatic, ​covered with three or four verticils of four long curved bristles; at the distal apex inflated, with four crossed, divergent, stout, curved horns. Around the pyramidal base of each spine a corona of eight pores (two on each of the four faces). Mouth cruciform, with four triangular, convergent teeth.
Dimensions.—Diameter of the shell 0.16, length of the spines 0.18.
Habitat.—South Pacific, Station 298, depth 2225 fathoms.
Genus 712. Circospathis, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Circoporida with a subregular, spherical, or polyhedral shell, composed of fourteen triangular, nearly equal plates, with nine corners, from, which arise nine radial spines, symmetrically disposed.
The genus Circospathis exhibits the remarkable and peculiar form of a "Tetradecahedron," or a subregular polyhedron with fourteen triangular faces, thirty edges, and nine corners, from which arise nine radial spines. These lie in three meridional planes, which are crossed at equal angles (three equidistant spines in each plane). The same interesting form occurs also in some Astrosphærida, which bear nine regularly disposed radial spines, as Haliomma echinaster. All four observed species of Circospathis are South Atlantic.
1. Circospathis furcata, n. sp. (Pl. 115, figs. 4-6).
Shell polyhedral or nearly spherical, with nine prominent corners, from which arise nine radial spines, about as long as the diameter of the shell. The polygonal plates of the shell are separated by high crests, usually hexagonal or pentagonal, irregular, about twelve to fifteen on the half meridian. Radial spines cylindrical, straight, about as long as the diameter of the shell, with spirally turned edges, covered with numerous curved bristles, at the distal end forked; the two fork branches curved, one-third as long as the simple basal part. The inflated base of each spine is surrounded by a corona of nine to twelve ovate basal pores. Mouth pentagonal, with five thick, mammillate and spinulate, somewhat convergent teeth (fig. 5).
Dimensions.—Diameter of the shell 0.6, length of the spines 0.5.
Habitat.—South Atlantic (east of Buenos Ayres), Station 325, depth 2650 fathoms.
2. Circospathis novena, n. sp. (Pl. 117, figs. 3, 3a).
Shell polyhedral (tetradecahedral), with fourteen triangular, plane, or slightly convex faces, covered with small, irregular, polygonal (usually hexagonal) plates, and nine prominent corners, from which arise nine radial spines, shorter than the diameter of the shell. Each spine is surrounded at the broader base by a circle of twelve to sixteen pores and a corona of bristles, and bears at the ​inflated distal apex a trident or fuscina, similar to that of Circoporus sexfuscinus (Pl. 115, fig. 2). Mouth with nine convergent, conical, denticulate teeth (fig. 3a).
Dimensions.—Diameter of the shell 0.6, length of the spines 0.4.
Habitat.—South Atlantic, Station 318 (east of Patagonia), depth 2040 fathoms.
3. Circospathis tetradeca, n. sp.
Shell spherical, covered with irregular, polygonal plates. Nine radial spines, cylindrical, as long as the radius of the shell, bristly, armed at the distal apex with a trident. (In one specimen six spines possessed three terminal branches, two spines two branches, and one spine four branches.) The broader base of each spine is surrounded by a corona of nine pores and a circle of curved bristles. Mouth with nine smooth conical teeth.
Dimensions.—Diameter of the shell 0.55, length of the spines 0.3.
Habitat.—South Atlantic, Station 332 (west of Tristan da Cunha), depth 2200 fathoms.
4. Circospathis tetrodonta, n. sp. (Pl. 115, fig. 10).
Shell subspherical or polyhedral, with fourteen triangular, convex faces, covered with irregular polygonal plates. Nine radial spines cylindrical, nearly smooth, about as long as the diameter of the shell; at the distal apex with four strong curved horns, like those of Circoporus hexastylus, Pl. 117, fig. 4. Each spine is surrounded at the base by a corona of nine irregular pores. Mouth with four large, prominent, conical teeth, which are spinulate, with vertical inner edge (fig. 10).
Dimensions.—Diameter of the shell 0.5, length of the spines 0.45.
Habitat.—South Atlantic, Station 323 (east of Buenos Ayres), depth 1900 fathoms.
Genus 713. Circogonia, n. gen.
Definition.—Circoporida with a regular icosahedral shell, composed of twenty congruent, triangular plates, with twelve corners, from which arise twelve radial spines.
The genus Circogonia is remarkable for the regular icosahedral form of its shell, a geometrical fundamental form, which occurs very rarely in organised bodies (as in Aulacantha icosahedra, and in some Astrosphærida with twelve regularly disposed radial spines). The shell is composed of twenty triangular, equilateral and congruent plates, which are sometimes separated by prominent crests; their surface is panelled by smaller hexagonal or polygonal secondary plates. The thirty edges between the plates are sometimes thickened. From the twelve corners of the regular icosahedron (where every five triangular plates meet), twelve equal radial spines arise, each of which is surrounded at the base by a corona of nine to sixteen pores. Two species only of Circogonia have been observed; the one has smooth spines, forked at the distal end, ​the other bears numerous curved bristles around each spine, and at the distal end a verticil of five curved branches. The mouth of the shell (placed in the centre of one of the triangular plates) is in both species armed with six teeth. Both species are found in the Tropical Atlantic.
1. Circogonia icosahedra, n. sp. (Pl. 117, figs. 1, 1a).
Shell regularly icosahedral, with twenty equal, triangular, nearly plane faces, which are separated by thirty prominent, crest-like edges, and covered by a delicate network of small, subregular, hexagonal plates. Twelve radial spines nearly conical, one and a half times as long as the radius of the shell, with five prominent edges. The campanulate base of each spine is covered with numerous long, curved bristles, surrounded by a circle of twelve to sixteen ovate, irregular pores, and separated from the slender distal part by a constriction. The distal apex of the spine is surrounded by a verticil of five conical, curved branches (corresponding to the five edges of the spines, and to the five faces, which meet in the corners where the spine arises). Mouth hexagonal, with six conical, spinulate teeth, convergent towards its centre (fig. 1a).
Dimensions.—Diameter of the shell 0.75, length of the spines 0.5.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
2. Circogonia dodecacantha, n. sp. (Pl. 115, figs. 8, 9).
Shell subregularly icosahedral, with twenty equal, triangular, slightly convex faces, which are not separated by prominent crests, but covered with a network of irregular polygonal plates. Twelve radial spines, cylindrical, smooth, about as long as the diameter of the shell, forked at the distal end with two divergent, slightly curved branches (similar to Circospathis furcata, Pl. 115, figs. 4-6). The conical base of each spine is surrounded by a circle of nine to twelve irregular, ovate pores (fig. 9). Mouth circular, with a corona of six conical, smooth teeth which arise perpendicularly from the shell (in the upper part of fig. 8, at left).
Dimensions.—Diameter of the shell 0.6, length of the spines 0.7.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
Genus 714. Circorrhegma, n. gen.
Definition.—Circoporida with a regular dodecahedral shell, composed of twelve congruent, pentagonal plates, with twenty corners, from which arise twenty radial spines.
The genus Circorrhegma is remarkable for the geometrical regularity of its shell, which represents a pentagonal dodecahedron. The shell is therefore composed of twelve equal and regular pentagonal plates, and these are separated in the only known ​species by thirty prominent crest-like edges. From the corners of the dodecahedron, at which every three pentagons meet, arise twenty radial spines, opposite in pairs in ten equidistant axes.
1. Circorrhegma dodecahedra, n. sp. (Pl. 117, figs. 2, 2a).
Shell dodecahedral, with twelve equal and regular, plane, pentagonal plates, which are separated by thirty prominent crests, and bear a network of numerous polygonal (usually also pentagonal), smaller plates. Twenty radial spines about as long as the radius of the shell, three-sided prismatic, covered with numerous bristles; each surrounded at the thickened base by a circle of twelve to sixteen pores, and at the distal apex by a corona of five curved, terminal branches. Mouth pentagonal, with five conical, subvertical, spinulate teeth (fig. 2a).
Dimensions.—Diameter of the shell 0.8, length of the spines 0.5.
Habitat.—Indian Ocean, Madagascar (Rabbe).
Genus 715. Circostephanus, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 5.
Definition.—Circoporida with a subregular, polyhedral or nearly spherical shell, composed of thirty to sixty or more triangular plates, with twenty-four to thirty-two or more corners, from which arise radial spines, symmetrically disposed.
The genus Circostephanus comprises those Circoporida in which the porcellanous shell is an endospherical polyhedron, with numerous (thirty to sixty or more) triangular faces, and has a variable number of radial spines (twenty-four to forty or more), arising from its corners. The number of faces and corners seems to be variable in this genus, but may perhaps be typical in some species. Circostephanus sexagenarius has the typical form of a "Sexagenal-Polyhedron," with sixty equal triangular faces and thirty-two corners, and may be derived from the "Pentagonal-Dodecahedron" (Circorrhegma) by dividing its twelve pentagonal faces each into five congruent triangles.
1. Circostephanus coronarius, n. sp. (Pl. 116, figs. 3, 3a, 3b).
Shell polyhedral, with thirty-two to forty triangular, concave faces of nearly equal size, which are separated by high prominent crests. From the elevated corners of the polyhedron arise twenty-four to thirty radial spines, which are three-sided prismatic or nearly cylindrical, about as long as the radius of the shell, and covered with long curved bristles. The distal end of each spine is surrounded by a verticil of five stout, curved branches, its pyramidal base by a corona of five (or ​sometimes six) ovate, basal pores (fig. 3b). Mouth armed with a corona of eight short, conical, vertical, spinulate teeth (fig. 3a).
Dimensions.—Diameter of the shell 0.4 to 0.5, length of the spines 0.2 to 0.25.
Habitat.—South-Eastern Pacific (off Valparaiso), Station 298, depth 2225 fathoms.
2. Circostephanus sexagenarius, n. sp.
Shell polyhedral, with sixty triangular, equilateral congruent faces which are nearly plane, and separated by high prominent crests. They are disposed in twelve pentagonal groups, each with five faces, so that they appear as if derived from a regular pentagonal dodecahedron, the twelve regular faces of which are each divided into five congruent triangles, meeting in its centre. From the elevated corners of the polyhedron arise thirty-two radial spines (twelve in the central points of the pentagons, twenty in the meeting corners of every three pentagons). The radial spines are nearly as long as the diameter of the shell, cylindrical, spinulate, and surrounded at the distal end by a verticil of five stout, curved branches, and at the pyramidal base by a corona of twelve to sixteen basal pores. Mouth armed with a corona of twelve conical, vertical, spinulate teeth.
Dimensions.—Diameter of the shell 0.75, length of the spines 0.6.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
3. Circostephanus polygonarius, n. sp.
Shell polyhedral, with sixty to eighty subregular, triangular, concave faces, which are separated by prominent crests. From the elevated corners of the polyhedron arise thirty to forty radial spines, which are longer than the diameter of the shell, densely covered with curved bristles and three-sided prismatic, with three spirally convoluted edges. Their distal end is surrounded by a verticil of eight or nine curved branches, and their pyramidal base by a corona of eight or nine basal pores. Mouth armed with a corona of ten conical, vertical, spinulate teeth.
Dimensions.—Diameter of the shell 0.8, length of the spines 0.9.
Habitat.—South Pacific, Station 288, depth 2600 fathoms.
Subfamily 2. Haeckelinida.
Definition.—Circoporida with dimpled spherical shell, not composed of polygonal plates. The shell is covered with small roundish dimples, never polyhedral, and the radial spines are simple, not branched, and usually not regularly arranged.
Genus 716. Haeckeliana, John Murray, 1879, in schedulis, Chall. Coll.
Definition.—Circoporida with spherical shell of a peculiar dimpled, porcellanous structure, and with a variable number of simple radial main-spines which are usually not regularly arranged.
​The genus Haeckeliana comprises the spherical Circoporida, with dimpled, porcellanous shell, which are widely distributed, but rather rare, in depths between 2000 and 3000 fathoms. All the known species (six in number) are very closely related, and though the extreme forms appear very different in size and structure, they are so connected by a continuous series of intermediate forms, that they may be regarded as varieties of a single species, first observed by Dr. John Murray, and called by him Haeckeliana porcellana. The number of radial spines may be from sixteen to fifty-five, and is usually between thirty and forty. Each is surrounded by a basal coronet of aspinal pores, usually five, more rarely four or six; the number, however, is not constant in any one species. Each coronet is armed with an outer ring of by-spines. The surface of the shell between the coronets is dimpled. The mouth (Pl. 114, fig. 3) is about as large as a corona, and also armed with a ring of by-spines. The structure of the thick porcellanous shell and the radial spines is different from the other Circoporida.
1. Haeckeliana porcellana, John Murray (Pl. 114, fig. 6).
Shell with forty to forty-five coronets, the majority of which have five pores (more rarely four or six). Coronets broader than their intervals, and twice as broad as the length of the by-spines. Dimples subcircular, of the same breadth as the pores. Main-spines about as long as the radius.
Dimensions.—Diameter of the shell 0.37 to 0.42, of the coronets 0.06 to 0.07.
Habitat.—South Pacific, Stations 289 to 293, depth 2025 to 2550 fathoms.
2. Haeckeliana maxima, n. sp. (Pl. 114, fig. 5).
Shell with fifty to fifty-five coronets, the majority of which have six pores (more rarely five or seven). Coronets broader than their intervals, and eight to ten times as broad as the length of the by-spines. Dimples irregularly polygonal, of about the same breadth as the pores. Radial main-spines about as long as the diameter of the shell.
Dimensions.—Diameter of the shell 0.5 to 0.52, of the coronets 0.08 to 0.09.
Habitat.—Equatorial Atlantic, Station 347, depth 2250 fathoms.
3. Haeckeliana lamarckiana, n. sp. (Pl. 114, fig. 4).
Shell with thirty-five to forty coronets, the majority of which have five pores (more rarely six or four). Coronets broader than their intervals; each funnel-shaped pore on the inside with a circle of small conical thorns. By-spines rudimentary or wanting. Dimples irregularly polygonal, half as broad as the pores. Radial main-spines shorter than the radius.
Dimensions.—Diameter of the shell 0.38 to 0.45, of the coronets 0.06 to 0.07.
Habitat.—South Atlantic, Stations 318 to 333, depth 2000 to 2900 fathoms.
​4. Haeckeliana murrayana, Haeckel.
Shell with twenty to twenty-five coronets, the majority of which have five pores (more rarely four or six). Coronets of about the same breadth as their intervals, and twice as broad as the by-spines. Dimples subcircular, of about the same breadth as the pores. Radial main-spines about as long as the radius.
Dimensions.—Diameter of the shell 0.35 to 0.4, of the coronets 0.06 to 0.07.
Habitat.—Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.
5. Haeckeliana goetheana, n. sp. (Pl. 114, fig. 3).
Shell with sixteen to twenty coronets, the majority of which have four pores (more rarely five and very rarely six). Coronets smaller than their intervals. By-spines very short or rudimentary. Dimples subcircular, half as broad as the pores. Radial main-spines shorter than the radius.
Dimensions.—Diameter of the shell 0.25 to 0.3, of the coronets 0.04 to 0.05.
Habitat.—North Pacific (south of Japan), Station 231, depth 2250 fathoms.
6. Haeckeliana darwiniana, n. sp. (Pl. 114, figs. 1, 2).
Shell with twenty-six to thirty-two coronets, the majority of which have five pores (rarely four or six). Coronets smaller than their intervals and than the length of the by-spines. Dimples subcircular, half as broad as the pores, Radial main-spines longer than the radius.
Dimensions.—Diameter of the shell 0.30 to 0.42, of the coronets 0.07 to 0.08.
Habitat.—North Pacific (east of Japan), Stations 241 to 245, depth 2300 to 2900 fathoms.
Family LXXXII. Tuscarorida, n. fam. (Pl. 100).
Definition.—Phæodaria with an ovate, spindle-shaped, or nearly spherical shell exhibiting a peculiar solid porcellanous structure; with a few radial pores around the base of the hollow tubules, which are symmetrically arranged around the main axis and the mouth. Surface of the shell smooth or spiny, not tabulate nor panelled. Central capsule excentric, placed in the aboral half of the shell-cavity.
The Tuscarorida, and the preceding closely allied family, the Circoporida, represent together a peculiar small group, which differs from the other Phæodaria in the singular porcellanous structure of the shell-wall, and may be called Phæocalpia; their hollow radial spines are distinguished by peculiar basal pores, forming a circle around their base. The shell of the Tuscarorida is monaxonian, ovate, spindle-shaped ​or nearly spherical, whilst in the Circoporida it is polyaxonian, spherical or polyhedral; the hollow radial spines are arranged in the former around the main axis, in the latter around the common central point. All Phæocalpia (the Tuscarorida as well as the Circoporida) are inhabitants of great depths, usually between 2000 and 3000 fathoms.
Though the number of Tuscarorida at present known is small (only three genera, with ten species), they represent a very distinct and remarkable family of Phæodaria, as well by their considerable size, as by the peculiar arrangement of the radial spines and the structure of the shell-wall, which in some species is more solid and thicker than in any other Radiolaria. The diameter of the shell is always more than 1 mm., usually between 1 and 2, and sometimes more than 3 mm.
The dry shell of the Tuscarorida is not hyaline and transparent as is usual in the other Radiolaria, but perfectly opaque, milk-white or yellowish-white. This opacity is caused by innumerable very fine pores, which everywhere pierce the thick, apparently solid, fundamental substance of the shell-wall. Besides those very small pores, it is also pierced by a certain number of larger pores, which are scattered at wide distances (Narr. Chall. Exp., vol. i. pl. A, fig. 15b). These larger pores or pore-channels have a diameter of about 0.01 mm., and pierce the shell-wall either in a perpendicular or in an oblique direction. Very numerous straight, simple, and thin needles, usually 0.1 to 0.2 mm. in length, similar to the thin tangential needles of the Aulacanthida, are everywhere scattered tangentially in the cement-like fundamental substance, which seems to be a peculiar carbonic silicate; their axis is parallel to the shell-surface.
The general form of the shell is somewhat different in the three genera of Tuscarorida; ovate or spherical in Tuscarora and Tuscarusa, which bear no caudal axial spine (Pl. 100, figs. 1-7), or sometimes three-sided pyramidal (fig. 4); it is spindle-shaped in Tuscaridium, which bears on the aboral pore an axial caudal spine (Pl. 100, fig. 8). In every case the main axis of the shell, determining its monaxonian fundamental form, is indicated by the mouth, which is placed in the oral pole of the main axis and prolonged into a short tube or proboscis.
The hollow apophyses, arising from the shell of the Tuscarorida, are always cylindrical, long and thin tubules, the narrow cavity of which communicates directly with the large shell-cavity. In the axis of the tubules lies a thin axial chord or funicle, composed of a few (usually three or four) siliceous threads which arise from bridges between the basal pores of the apophyses, and are twisted together like the strands of a rope. The axial funicle is connected with the thin wall of the tubular apophyses by innumerable very thin radial beams, perpendicular to the axis (Pl. 100, fig. 3a, 5b). The surface of the apophyses is almost constantly covered with numerous small bristles or spines, which are usually curved and directed towards their distal ends.
Tuscarora (Pl. 100, figs. 1-6) exhibits two different groups of apophyses, which may be distinguished according to their different position and direction as "circoral ​teeth" and "aboral feet"; the teeth immediately surround the opening of the mouth, whilst the feet are remote from it and usually placed in the aboral half of the body, more rarely in the equator or in the oral half. The general form and structure are the same in both groups of apophyses, but their position and direction is different; the circoral teeth are directed forwards, often parallel (at the base at least), while the aboral feet are either divergent and directed backwards, or they diverge forwards in the basal part, then form a large arch, and finally curve backwards.
The number of the aboral feet, and their position relative to the circoral teeth, are different but probably constant in each single species, and serve, in the first place, for the distinction of genera and species. Tuscarora (in restricted sense) (Pl. 100, figs. 1-6), has constantly three feet (comparable to the three cortinar feet of the tripodal Nassellaria); Tuscarusa (Pl. 100, fig. 7) has four feet, opposite in pairs and forming a regular cross; Tuscaridium, finally (Pl. 100, fig. 8), has only one foot, which is situated in the main axis, on its aboral pole, and may therefore be called a caudal spine.
The number of the circoral teeth varies from two to four, and is usually three. Originally these three teeth alternate regularly with the three aboral feet, so that the latter may be regarded as perradial, the former as interradial (Pl. 100, figs. 1-4). The proportion of the number of each group of apophyses in the different species is synoptically shown in the following table:—
| | | Depth in Fathoms. | Challenger Station. | Length of the Shell. | Breadth of the Shell. | Number of Feet. | Number of Pedal Pores. | Number of Teeth. | Number of Dental Pores. |
| 1. | Tuscarora bisternaria, | 3000 | 264 | 2.0 | 1.5 | 3 | 8 | 3 | 8 |
| 2. | Tusc"rora murrayi, | 2000 | 295 | 2.5 | 1.5 | 3 | 3 | 3 | 3 |
| 3. | Tusc"rora wyvillei, | 2250 | 291 | 1.5 | 1.4 | 3 | 4 | 3 | 4 |
| 4. | Tusc"rora tetrahedra, | 2450 | 348 | 2.5 | 2.0 | 3 | 4 | 3 | 3 |
| 5. | Tusc"rora tubulosa, | 3000 | 249 | 1.4 | 1.2 | 3 | 4 | 2 | 3 |
| 6. | Tusc"rora porcellana, | 2650 | 325 | 1.5 | 1.3 | 3 | 4 | 2 | 4 |
| 7. | Tusc"rora belknapii, | 2025 | 293 | 2.5 | 1.5 | 3 | 3 | 4 | 2 |
| 8. | Tuscarusa medusa, | 3125 | 253 | 1.2 | 1.0 | 4 | 4 | 2 | 2 |
| 9. | Tuscaridium cygneum, | 3050 | 250 | 3.2 | 1.6 | 1 | 2 | 4 | 4 |
| 10. | Tusca"idium lithornithium, | 3000 | 264 | 3.6 | 1.8 | 1 | 4 | 4 | 6 |
The base of the apophyses in all Tuscarorida is inflated, conical, and pierced by a small number of large ovate pores, the typical "basal pores," which occur also in the closely allied Circoporida. The number of these basal pores varies from two to eight, and is usually three or four; it never becomes in this family so great as in the Circoporida, where each circle of pores is often composed of sixteen to twenty-four or more basal pores. The number seems to be rather constant in each single species, as may be seen in the preceding Table. The pedal pores (on the base of the aboral feet) are usually larger than the dental pores (on the base of the circoral teeth). Their form is ​usually irregularly ovate or triangular; their outer aperture is armed with spines or bristles, which are commonly larger than in the other parts of the apophyses.
The mouth of the shell varies in form, according to the number and arrangement of the teeth on its corners. It is therefore a narrow transverse fissure, with two broad opposite lips and two corners, in the bidental forms (Pl. 100, figs. 5, 7), triangular in the tridental species (figs. 1-4), quadrangular or square in the quadridental species, Tuscarora belknapii (Narr. Chall. Exp., loc. cit., pl. A, fig. 15). The singular genus Tuscaridium (fig. 8) exhibits four teeth, which are nearly horizontally divergent in two pairs, a dorsal and a ventral pair (corresponding in position to the four feet of Tuscarusa, fig. 7); the mouth is here prolonged into a cylindrical, spinulate proboscis, which is curved towards the ventral face of the shell (fig. 8).
The central capsule of the Tuscarorida is kidney-shaped or spheroidal, scarcely half as large as the dark olive-green phæodium, which surrounds its anterior (oral) face. Usually the capsule and the phæodium together fill up the aboral half of the shell-cavity, and are separated from its walls by the calymma. The latter is pierced by numerous branched and reticulately anastomosing pseudopodia, which arise from the matrix enveloping the capsule, and pass over into a thin layer of sarcode, adjacent to the inner surface of the shell. The astropyle or the main-opening of the central capsule exhibits the usual radiate operculum and tubular proboscis of the Phæodaria (Pl. 115, fig. 3), and is directed towards the mouth of the shell. The number of the parapylæ or accessory openings seems to be variable in this family, and to correspond to the number of radial feet which arise from the shell. Therefore Tuscaridium possesses only one parapyle, which is diametrically opposite to the mouth, lies on the aboral pole of the capsule, and is directed towards the single caudal tube. Tuscarora seems to have three parapylæ, corresponding to the three radial feet, and Tuscarusa probably has four parapylæ, directed towards its four radial feet; in the latter genus, however, the capsule was not observed (the shell being empty); and in the other Tuscarorida this important and difficult anatomical question must be solved by further accurate examinations.
The nucleus is nearly half as large as the central capsule, ellipsoidal, and contains numerous nucleoli. In one specimen of Tuscarora belknapii I observed two nuclei in the central capsule, and in another specimen of the same species John Murray observed two central capsules (figured by him in the Narr. Chall. Exp., vol i. pl. A, fig. 15).
Synopsis of the Genera of Tuscarorida.
| Three equidistant aboral radial feet, | 717. Tuscarora. |
| Four equidistant aboral radial feet, | 718. Tuscarusa. |
| One single aboral foot or terminal spine, | 719. Tuscaridium. |
Genus 717. Tuscarora, John Murray, 1876, in schedulis, Chall. Coll.
Definition.—Tuscarorida with three radial aboral feet, and a variable number of circoral teeth.
The genus Tuscarora comprises seven of the ten observed species of Tuscarorida, all seven agreeing in the possession of three perradial feet, which alternate originally (in four species), with three interradial teeth surrounding the mouth. The latter is armed in two other species with two teeth, and in one species with four teeth (compare above, p. 1704). The three perradial feet have a similar position as in the tripodal Nassellaria, so that they may be distinguished as an odd caudal foot and two paired lateral feet.
Subgenus 1. Tuscarantha, Haeckel.
Definition.—Shell with three perradial equidistant feet and three interradial equidistant circoral teeth, alternating regularly with the former.
1. Tuscarora bisternaria, John Murray (Pl. 100, figs. 1, 1a).
Shell subspherical, with three lateral perradial feet in the equatorial zone, and three basal interradial teeth around the mouth, alternating regularly with the former. The three lateral feet arise either in the equator itself or a little above it, and are nearly horizontally expanded, descending a little towards the aboral pole. They are straight, cylindrical, twice to four times as long as the shell, geniculate at the inflated base, and covered with small thorns. A circle of six to eight basal pores in the base of each foot. The narrow mouth is triangular, surrounded by the thorny, inflated, subspherical bases of the three long, cylindrical, diverging, thorny teeth, which ascend obliquely and are longer than the shell; each tooth exhibits in the upper part of the inflated base a corona of eight to ten ovate holes.
Dimensions.—Length of the shell 2.0, breadth 1.5.
Habitat.—Central Pacific, Station 264, depth 3000 fathoms.
2. Tuscarora murrayi, n. sp. (Pl. 100, fig. 2). John Murray, 1876, L. N. 27, pl. 24, fig. 4.
Shell pear-shaped, with three circoral perradial feet in the upper third and three basal interradial teeth around the mouth. The three lateral feet are thin, cylindrical, arcuate, very bristly, arise immediately beyond the narrow tubular peristome, and ascend obliquely nearly to the height of the mouth; then they are curved downwards in a large arc, three to four times as long as ​the shell. The tubular peristome is about half as long as the shell, bottle-shaped, nearly three-sided prismatic, and bears three very long spinulate teeth, which in the lower half are parallel, in the upper slightly curved and diverging, at the base pear-shaped. Three ovate basal pores in the inflated base of each foot and each tooth.
Dimensions.—Length of the shell 2.5, breadth 1.5.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
3. Tuscarora wyvillei, n. sp. (Pl. 100, figs. 3, 3a-3c).
Shell subspherical, pellucid, thinner and more fragile than in the other species of the genus, with three aboral perradial feet in the lower third, and three interradial teeth around the wide mouth. The three feet are straight, conical, widely divergent, shorter than the shell, and arise from its lower third; on the inflated base of each four small ovate pores. The three teeth, alternating with them, are straight, cylindrical, arise from the margin of the mouth and diverge obliquely upwards. On the base of each foot four opposite cordate pores of very unequal size.
Dimensions.—Length of the shell 1.5, breadth 1.4.
Habitat.—South Pacific, Station 291, depth 2250 fathoms.
4. Tuscarora tetrahedra, John Murray (Pl. 100, figs. 4, 4a).
Shell tetrahedral or three-sided pyramidal, with three perradial basal feet, and three alternate, interradial, circoral teeth. The three rounded edges of the pyramid are prolonged directly over the aboral base into the three short, divergent, conical, basal feet, which are smooth and scarcely one-fourth as long as the shell. The base of each foot is pierced by four small crossed pedal pores. The narrow mouth, on the apex of the pyramid, is surrounded by three short and broad, triangular, spinulate teeth, each of which bears three slender, triangular, dental pores.
Dimensions.—Length of the shell 2.5, breadth 2.0.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
Subgenus 2. Tuscaretta, Haeckel.
Definition.—Shell with three perradial equidistant feet, and with two circoral teeth, which are opposite in the radius of the odd dorsal foot; therefore a dorsal and a ventral tooth.
5. Tuscarora tubulosa, John Murray (Pl. 100, figs. 5, 5a, 5b).
Shell subspherical, with three lateral perradial feet on the upper half of the shell (above the equator), and two parallel vertical teeth on the mouth. The three feet arise between the upper and ​the middle third of the shell, diverge upwards, and are slightly arcuate, covered with numerous curved spines. Their base is pierced by four pedal pores. The peristome is a narrow sagittal fissure, placed in the radius of the odd or dorsal foot, and bears two opposite teeth on its two corners. The teeth are cylindrical, longer than the shell, covered with curved spines, and ascend in a parallel and vertical manner; each is perforated at the base by three large dental pores.
Dimensions.—Length of the shell 1.4, breadth 1.2.
Habitat.—North Pacific, Stations 244 to 250, depth 2050 to 3050 fathoms.
6. Tuscarora porcellana, John Murray (Pl. 100, figs. 6a, 6b).
Shell pear-shaped, with three lateral perradial feet in the lower half of the shell, and two parallel vertical teeth on the mouth. The three lateral feet arise between the middle and the lower third of the shell, are straight, cylindrical, spinulate, about as long as the shell and diverge downwards; their base is pierced by four ovate pedal pores. The two parallel and vertical teeth are straight, shorter than half the shell, and opposite in the sagittal plane, on the two corners of the narrow mouth, in the radius of the dorsal odd foot. The base of each tooth exhibits four cordate dental pores.
Dimensions.—Length of the shell 1.5, breadth 1.3.
Habitat.—South Atlantic, Station 325, depth 2650 fathoms.
Subgenus 3. Tuscarilla, Haeckel.
Definition.—Shell with three perradial equidistant feet, and with four crossed equidistant teeth around the mouth.
7. Tuscarora belknapii, John Murray.
Shell pear-shaped, with three lateral perradial feet in the upper third, and four crossed teeth around the mouth. The three arcuate feet are thin, cylindrical, covered with small curved thorns, and arise at the base of the peristome, between the upper and middle third of the shell; they ascend diverging to the height of the mouth, and are then curved downwards in a large arc, twice to three times as long as the shell. The base of each foot is dilated and pierced by three pedal pores. The four thin and long teeth of the peristome are similar to the feet, ascend in a slightly diverging manner, and are so placed that two opposite lie in the sagittal plane (or in the radius of the dorsal odd foot), whilst the two others are opposite in the frontal plane (perpendicular to the former). The base of each tooth exhibits two large ovate dental pores.
Dimensions.—Length of the shell 2.5, breadth 1.5.
Habitat.—South Pacific, Station 293, depth 2025 fathoms.
Genus 718. Tuscarusa, n. gen.
Definition.—Tuscarorida with four radial aboral feet and a variable number of circoral teeth.
The genus Tuscarusa differs from the preceding closely allied Tuscarora in the possession of four radial feet instead of three. The mouth of the single observed species is a narrow sagittal fissure, and armed with two opposite teeth (a dorsal and a ventral, as in the subgenus Tuscaretta). The four lateral feet form a cross, and lie opposite in pairs, in two diagonals of the square, which is bisected by the sagittal mouth.
1. Tuscarusa medusa, n. sp. (Pl. 100, figs. 7, 7a).
Shell ovate, with four crossed lateral feet in the upper third, and with two opposite teeth around the mouth. The four feet are opposite in pairs in two diameters of the shell, perpendicular one to another, and arise between the upper and middle third of the shell; they are thin, cylindrical, spinulate, arcuate, and ascend to the height of the mouth diverging upwards; then they are curved downwards in a large arc. They lie in the diagonals of the square, which is halved by the narrow and long fissure of the mouth. This lies in the original sagittal plane, and from its two corners arise the two opposite teeth (a dorsal and a ventral), diverging upwards, cylindrical and slightly curved. The base of each foot is pierced by four pedal pores, of each tooth by two dental pores.
Dimensions.—Length of the shell 1.2, breadth 1.0.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
Genus 719. Tuscaridium, n. gen.
Definition.—Tuscarorida without radial aboral feet, but with a terminal axial caudal foot, and a variable number of circoral teeth.
The genus Tuscaridium, comprising two closely allied species, differs from the two preceding genera of Tuscarorida in the absence of lateral radial feet, which are represented by a single large caudal spine placed in the main axis of the shell, at its aboral pole. The shell is therefore spindle-shaped, and not ovate or subspherical, as in the two other genera. It reaches in the two observed species a length of more than 3 mm.
1. Tuscaridium cygneum, Haeckel.
Shell spindle-shaped, twice as long as broad (in the transverse section circular), equally tapering towards both poles of the main axis. The aboral pole bears a thin, cylindrical, straight, caudal ​spine, placed in the prolongation of the main axis, and about half as long as the shell. Its base is pierced by two large opposite pedal pores. The anterior or oral pole bears a cylindrical peristome, similar to a bird's head, and curved towards the ventral face; on both sides of its neck (at right and left) a series of three or four irregular, ovate, buccal holes. The neck bears four cylindrical, spinulate, radial tubes (two on each side), crossed nearly horizontally, and placed in two diagonal planes perpendicular one to another; these planes correspond to those in which the four feet of Tuscarusa medusa lie. The base of each tube is pierced by four dental pores.
Dimensions.—Length of the shell 3.2, breadth 1.6.
Habitat.—North Pacific, Station 250, depth 3050 fathoms.
2. Tuscaridium lithornithium, n. sp. (Pl. 100, figs. 8, 8a, 8b).
Shell spindle-shaped, twice as long as broad, very similar to the preceding closely allied species. It differs from the latter in the following characters:—The curved proboscis of the peristome is broader and more spiny. The four radial tubes of the mouth and the terminal caudal spine are very spiny (in the preceding species nearly smooth). The number of buccal holes (six to eight on each side of the mouth) is twice as great as in the former. Each circoral tube is pierced at the base by six or eight (in the former by four pores), and the base of the caudal spine exhibits a cross of four pores (in Tuscaridium cygneum only two pores).
Dimensions.—Length of the shell 3.6, breadth 1.8.
Habitat.—North Pacific, Station 264, depth 3000 fathoms.
* ↑ Lithogromia = Siliceous Gromia.
* ↑ Entocannula Shell with an internal tube.
* ↑ Pharyngella = Shell with an internal pharynx.
* ↑ Porcupinia, in memory of H.M.S. "Porcupine" by which the first British deep-sea explorations were carried out during the years 1869 and 1870.
* ↑ Cortinetta = Diminutive of Cortina.
* ↑ Medusetta = Small Medusa.
* ↑ Euphysetta = Diminutive of Euphysa (a Medusa).
* ↑ Gazelletta = Named in memory of the German ship "Gazelle," which was engaged in deep-sea soundings during the years 1874 to 1876, under the command of Captain Schleinitz (Naturalist, Professor Studer).
* ↑ Gorgonetta = Diminutive of Gorgo, Medusa.
* ↑ Polypetta = Diminutive of Polypus.
* ↑ Castanarium = Shell similar to a chestnut, Castanea.
* ↑ Castanella = Diminutive of Castanea.
* ↑ Castanidium = Small chestnut; καστανίδιον.
* ↑ Castanissa = Diminutive of Castanea.
* ↑ Castanopsis = Shell similar to a chestnut; κάστανον, ὄψις.
* ↑ Castanura = Chestnut with tails; κάστανον, ὀυρά.
* ↑ Circoporus = Shell with circles of pores; κίρκος, πόρος.
* ↑ Circospathis = Shell with verticils around the spines; κίρκος, σπαθίς.
* ↑ Circogonia = Polyhedron with circles of pores; κίρκος, γωνία.
* ↑ Circorrhegma = Shell with circles of fissures; κίρκος, ῥῆγμα.
* ↑ Circostephanus = Shell with circular coronets; κίρκος, στέφανος.
* ↑ Tuscarora, named from the American ship "Tuscarora," commanded by Captain Belknap, which made a splendid series of deep-sea soundings in the Pacific Ocean in 1875.
* ↑ Tuscarusa, derivation from Tuscarora.
* ↑ Tuscaridium, derivation from Tuscarora.