bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Parasitic Protozoa.
Authors: Mackinnon Doris L.
Published: April 2021

In 1911, I recorded from the intestine of trichopterous larvæ, a slipper-shaped flagellate with a relatively enormous cytostome. I named the organism Embadomonas, and pointed out that it showed affinities with Chilomastix Alexeieff, 1911 (Syn. Macrostoma, Alex., Tetramitus Alex.), from which it differed in its general form, and in the number of the flagella. The species from trichoptera I called E. agilis.
The Development of Alcyonium digitatum, with some notes on the Early Colony Formation.
Authors: Matthews Annie
Published: April 2021

The fertilised eggs segment in various ways, but typical morulæ always result. When the sixteen cell stage again divides to produce the thirty-two celled embryo, delamination occurs, and from now onwards the larva is two-layered. The morula at the twentieth hour begins to undergo a series of contortions which last from the first to the third day. This solid contorted stage is here termed the pre-planula, as it passes on into the hollow planula stage. The pear-shaped planula, while swimming, exhibits characteristic “planarian-like” movements, and on the fourth free-swimming day (the seventh day of development) it settles down by the broad anterior and aboral pole. The settled larva soon flattens, assuming a mound-like shape, and ou the second day of fixation eight mesenteries grow out simultaneously into the coelenteron from the base of the lateral wall. The cœlenteron is identical with the hollow entrai space in the endoderm of the planula. The mesenteries, arranged in four distinct pairs, grow simultaneously and rapidly along the lateral walls and attached base, and soon nearly meet on the basal and oral surfaces of the polyp. Many round cells now appear at the base of the columnar ectoderm. Mesoglœa is at this time secreted by the endoderm, and flows round the above-mentioned round ectoderm cells, cutting them off either singly or in groups. These isolated ectoderm cells produce either nematocysts or spicules, the spicules appearing soon after the mesenteries. Early on the third day eight simple hollow tentacles grow out, alternating with the mesenteries, and encircling the oral surface. Later on the third day the stomodæüm and moufli arise by the appearance of a rapidly deepening invagination of the oral surface, in the centre of the circle of tentacles. Yolky detritus is still present in the coelenteron. On the fourth day the base of this invagination degenerates, and so the coelenteron communicates with the exterior. While the mouth invagination is still in process of formation, the endodermic portion of the mesenteric filaments arises on the six ventral mesenteries by a proliferation of cells on the upper part of the free edge. On the fifth day the ventral mesenteric filaments are completed by strap-like ectodermic downgrowths from the stomodæum over the endodermic thickening on each mesentery. On the sixth day the dorsal mesenteric filaments arise. The dorsal and ventral mesenteric filaments appear homogeneous in origin, though of diverse function. On the seventh day the eight filaments reach about half way down the free edges of their respective mesenteries. Further development consists of elaboration of the organs already present. At the end of the third week the first bud is formed, and the solitary polyp becomes a young colony by stolonal gemmation. The young colonies were successfully fed in the laboratory on larvæ and adult individuals from colonies of Lepto-clinum and Botryllus.
On a Larval Actinian Parasitic in a Rhizostome
Authors: Badham C.
Published: April 2021

Our knowledge of the medusophilous larval Actinians has been summarised by Haddon (1) and by McMurrich (2). The last-named author says: “The available evidence seems accordingly to point strongly in favour of the various medusophilous forms being the young stages in the development of Peachia rather than Halcampa; but a direct linking-up of the immature examples of Bicidium1 with their respective adults is necessary to settle the question.”
On the Development of the Segments of the Head in Scyllium
Authors: Goodrich Edwin S.
Published: April 2021

The object with which this work was undertaken was to describe the development of the skull in Scyllium and the relation of its elements to the general segmentation of the head, more especially in the occipital region. But it soon became evident that our knowledge of the segmental composition of the head in Elasmobranchs is still in a very unsatisfactory condition, and that a re-investigation of the whole question was necessary. In addition, then, to an account of the development of the skeletal segments, a short history of the mesoblastic somites is given, and incidentally of certain points in the development of the nerves and other structures in the head region.
Reproduction by Transverse Fission in Phoronopsis
Authors: Gilchrist J.D.F.
Published: April 2021

The occurrence of asexual reproduction in the Phoronidea, though apparently an easy matter to determine, has not proved to be so. Species of Phoronis occur in groups of closely associated individuals or colonies, and it has often been observed that they have the power of casting off and rapidly regenerating the whole of the lophophoral or distal end of the body. Several observers have noted the occurrence, and the process of regeneration has been described in detail by Schultz, who also found that regeneration occurred in both parts of a Phoronis cut in two. Though the naturally detached part can be readily kept under observation, it was never found to develop into, a new individual, and this may be the reason why no suggestions were made of the possible reproduction of the animal by simple division of the body. In 1907 Selys-Longchamps (7), in repeating the experiments of Schultz, came to the conclusion that natural division of the body probably does occur, and that the animal reproduces in this way. It was not, however, until 1917 that any definite proof of this suggestion was brought forward, when Harmer (3), in his rediscovery of Phoronis ovalis, found definite evidence, which seems to place it beyond doubt that such an occurrence does take place.
On a Species of the Crawling Medusa, Eleutheria, from the Cape of Good Hope (Cnidonema capensis, g. et sp. n.) and the Southern Eleutheriæ
Authors: Gilchrist J. D. F.
Published: April 2021

A species of “Eleutheria” is found in fair abundance at certain times and places at the Cape of Good Hope. It can readily be kept in confinement, and some of its habits are noted. The chief characteristics of the species are described and compared with those of other southern species. Its hydroid form has been found, and proves to be very similar to that of Cladonema (Stauridia), not of Eleutheria (Clavatella). It differs, however, from Cladonema chiefly in the absence of oral tentacles, and a new genus (Cnidonema) is proposed for the reception of this and probably all the other southern Eleutheria, the hydroid forms of which, however, are not yet known.
The Terminology of Parthenogenesis
Authors: Lankester Sir Ray
Published: April 2021

The word “parthenogenesis “has become established in biological science to signify the production of offspring by a virgin mother. The term does not embrace reproduction by buds or by fission, but refers to parentage by a mother who produces egg-cells identical in character with those which, in the vast majority of instances, fuse with male sperm-cells before proceeding to develop. In those instances which are distinguished as instances of “parthenogenesis/’ the egg-cells proceed to develop without fusion with the male reproductive element or sperm-cell.
The Cytoplasmic Inclusions of the Germ-Cells
Authors: Galenby J. Brouté
Published: April 2021

this paper I have collected some notes on technique, with especial attention to various methods used for demonstrating and distinguishing between protoplasmic and deutoplasmic bodies. I have also added directions and a plan for research on the lines intoduced into this country by myself.
Observations on an Intra-nucleolar Body in Columnar Epithelium Cells of the Intestine
Authors: Carleton H. M.
Published: April 2021

The presence of one or more intra-nucleolar bodies in the columnar cells of the intestinal epithelium in the frog and cat has been demonstrated. To these inclusions the term “nucleolinus,”originally introduced by Haeckel, has been applied. By a modification of the Cajal technique for the Golgi apparatus, the nucleolinus has, in the frog’s intestine, been impregnated in a perfectly specific manner. The presence of nucleolini both in karyosomes (e.g. cat)and in plasmosomes (e.g. frog) in the columnar intestinal cells shows that they are not restricted to one of these types of nucleolus. Evidence has been adduced showing that division of the nucleolus (plasmosomes) in the resting cell is in all probability accompanied by fission of the nucleolinus. During mitosis the nucleolinus has been shown apparently to divide, a portion or portions of it being distributed to each of the daughter-nuclei. This is in contrast to the behaviour of the nucleolus (plasmosome), which disintegrates during cell division. The presence of the nucleolinus has been confirmed in the columnar cells of the intestinal mucosa in both the frog and the cat by other and simpler methods than the Cajal technique. The significance of the apparent continuity of the nucleolinus has been very briefly discussed.
On the Pharyngeal or Salivary Gland of the Earthworm.
Authors: Keilin D.
Published: April 2021

It is well known that the dorsal wall of the pharynx in all earthworms is much thickened, and forms a real pharyngeal bulb, which bulges prominently into the coelomic cavity. By dissection from the dorsal surface of the earthworm, this pharyngeal bulb can be easily seen with an ordinary lens and, in the larger specimens, even with the naked eye. It is richly vascularized and its surface is irregular and tabulated. In longitudinal median section the pharyngeal bulb is seen to be composed of the three following portions : (1) an external epithelial sheath, (2) a median mass of musculo-vascular tissue, and (3) an internal portion composed of aggregates of deeply-staining cells.
Further Studies on Restitution-bodies and free Tissue-culture in Sycon.
Authors: Huxley Julian S.
Published: April 2021

In a previous paper (Huxley, 7) I showed that the remarkable phenomena of regeneration from dissociated cells, first observed by H. V. Wilson (15) in monaxonid sponges, later extended by him (16) and by de Morgan and Drew (4) to coelenterates, could be studied in a simpler and more satisfactory form in hoterocoelous calcareous sponges than in any other types investigated. I further showed that, by certain metheds, restitution-bodies composed entirely or almost entirely of collar-cells could be produced, and that these assumed a form quite unlike anything found in normal sponges, but with a resemblance to a Choanoflagellate colony. Simple excess of collar-cells, or, apparently, larger masses composed almost entirely of collar-cells, led to the formation of what I called choanocyte blow-outs—a part of the solid mass becoming blown out to form the segment of a collar-cell sphere.
The Proboscis of the Syllidea. Part I. Structure.
Authors: Haswell W.A
Published: April 2021

The proboscis of the Syllidea (here taken as comprising all that part of the digestive tube lying in front of the intestine) is made up of five parts (fig. 6), which are all (with the exceptions presently to be noted) sharply marked off from one another. These will be referred to here as (1) the buccal chamber, (2) the pharynx, (3) the proventriculus, (4) the ventriculus, and (5) the post-ventriculus with a pair of caeca, appended to it.
The Life-history of Melicertidium octo-costatum (Sars), a Leptomedusan with a theca-less Hydroid Stage
Authors: F. Gemmill James
Published: April 2021

This -well-known medusa (fig. 19) is classified among the Thaumantiadae, and is characterized by the presence of eight ‘radial’ canals on which the gonads are developed. The marginal tentacles are numerous (up to 140) and of unequal size, larger and smaller ones alternating more or less regularly. There are no lithocysts, cordyli or ectodermal ocelli. The manubrium is short, the mouth four-angled and without oral tentacles. The medusa has a fairly wide distribution in the North-east Atlantic ranging from Bergen to Falmouth. (See E. T. Browne, 4, for details and a discussion of the nomenclature.) The hydroid, as I have ascertained by rearing the eggs, proves to be a hitherto undescribed species identical with one which has been noted for several years (with a year’s interval of absence) growing abundantly and spontaneously in the tanks at the Millport Biological Station.
On the Classification of Actiniaria.: Part II.—Consideration of the whole group and its relationships, with special reference to forms not treated in Part I1
Authors: Stephenson T. A.
Published: April 2021

It has been necessary, on account of the length of the present paper, to confine Part II to discussions; the definitions of families and genera involved, on the lines of those already given in Part I, will be printed in another issue of this Journal as Part III, which will also contain a list of literature and an index to genera covering Parts II and III. The list of literature will be additional to that printed in Part I, and any numbers given in brackets in the following pages will refer to the two lists as one whole.
The Development of the Sea Anemone Bolocera Tuediae (Johnst.)
Authors: Gemmill Janies F.
Published: April 2021

Bolocera tuediae was recorded and described from deep water near Berwick by Johnston (11) in 1832. Gosse described it more fully in 1860 (10, p. 185) and the following is his summary of its characters: ‘Base adherent, not much exceeding the column. Column pillar-like, the diameter and height sub-equal; surface generally very smooth, studded with warts remotely scattered. Disc smooth, circular in outline, not overlapping the column. Tentacles short, thick, constricted at foot, obtusely pointed, longitudinally furrowed, flexuous and motile, easily separated, not retractile. Mouth raised on a cone. Stomach capable of being greatly protruded.’ The tentacles are, however, moderately long and slender when fully extended during life.
The Early Development of the summer egg of a Cladoceran (Simocephalus vetulus)
Authors: Cannon H. Graham
Published: April 2021

1. Each egg is laid as a yolky mass of a foam and later forms a primary egg-membrane.

2. Cleavage is completely superficial and apparently indeterminate.

3. The first differentiation of the blastoderm is the appearance of a group of vacuolated yolky cells on the ventral side of the embryo which are called the ventral mass.

4. This subsequently differentiates into a few large cells with very large nuclei which form the genital rudiment, surrounded laterally and posteriorly by ectomesodermal cells, and anteriorly to this a mesendodermal mass of cells from which arises the mesendoderm.

5. The genital rudiment surrounded laterally and posteriorly by inwardly growing ectomesodermal cells invaginates and becomes internal by the lips of the invagination growing together and fusing.

6. The mesendoderm grows backwards as a solid mass of cells, which later spreads out flat and becomes indistinguishable from the laterally-lying mesoderm, and from this layer the endoderm separates as a solid rod in the median plane.
On the Labral Glands of a Cladoceran (Simocephalus vetulus), with a description of its mode of feeding
Authors: Cannon H. Graham
Published: April 2021

Leydig (12) in 1860 was the first worker to point out that the possession of labral glands is common to all the Cladocera. In 1846, however, Schödler (16) had observed that in the labrum of Acanthocercus there exist paired glandular bodies; he states, ‘Im sog. Labrum (des Acanthocercus) glauben wir ein paar rundliche, fast nierenformige Conglomerate als drüsige Körper (vielleicht als Speicheldrüsen, glandulao salivales) ansprechen zu müssen’. Claus (3) in 1876 mentioned these glands in his work on the anatomy of Daphnids, and later Cunnington (5) in 1903 described them in Simocephalus sima (Simocephalus vetulus).
The Segmentation of the Head in Squalus acanthias
Authors: de Beer G. Rylands
Published: April 2021

There are two views with regard to the segmentation of the head. One has arisen out of Balfour ‘s (1) pioneer work, the other is due to Van Wijhe (18). They both agree on many points, and the difference between them lies in the interpretation of the numerical relations of the different segmented structures, as pointed out by Goodrich (8). In order that they may be compared, a short account of these views will now be given.
Some Notes on the Gametogenesis of Ornithorhynchus Paradoxus
Authors: Gatenby J. Brontë
Published: April 2021

In this paper I have described in as much detail as was possible the oogenesis of the duck-billed platypus of Australia. Owing to the unique position of the Prototheria, any new facts with regard to their germ-cells is sure to be of value. I must take this opportunity of thanking Professor J. P. Hill, F.R.S., for allowing me to study his material of Ornithorhynchus, without which I could not have published these notes.
Note on the Comparative Effects on Tissues of Isotonic Saline and Distilled Water when used as Solvents for Mercuric Chloride and Formol in Histological Fixation
Authors: Carleton H. M.
Published: April 2021

Should a simple fixative such as mercuric chloride or formol be dissolved in normal (i. e. isotonic) saline or in water ? Curiously enough, observations are lacking on this simple but fundamental point.
Cannibalism in Amoeba vespertilio (Penard)
Authors: Lapage Geoffrey
Published: April 2021

This paper describes the temporary adoption by Amoeba vespertilio of cannibalistic habits. The amoebae frequently ingested, but in most cases failed to digest, other individuals of their own and also of other species (A. limax). In some cases, an amoeba, which had ingested another, might itself then be ingested by a third amoeba ; and these three might then be taken up by a fourth amoeba, so that remarkable figures, suggesting concentric fission, resulted. The victims were usually ingested while they were rounded off or sluggish, and, after extrusion, usually failed to resume their activity, although most of them developed contractile vacuoles and some showed tentative amoeboid movements. A few recovered their normal activity and resumed normal life. Amoebae, after extrusion by one amoeba, were often taken up again by other amoebae. In one case an Amoeba vespertilio was observed to chase and enclose an Amoeba limax, but the Amoeba limax subsequently escaped again. The ingested amoebae may easily be mistaken for endogenous buds, but there is less danger of their being mistaken for-parasites. No trustworthy evidence was found as to the nature of the stimulus which caused the adoption of these habits, but the question is discussed.
Some Observations upon the Development of the Teeth of Physeter macroeephalus.
Authors: Beddard Frank E.
Published: April 2021

On the following pages I describe the nature of the tooth rudiments in the very young embryo of Physeter macro-cephalus, whose general external characters I have already commented upon and figured (Beddard, 1). Since the material upon which I have worked is, so far as I am aware, a unique specimen only inches long 4 ½ I am particularly grateful to the Curator of the Durban Museum (Mr. E. C. Chubb) for placing it in my hands and to the authorities of the Museum of the Royal College of Surgeons of England for allowing their highly skilled assistant, Mr. Steward, to prepare a series of sections for study.
The ‘Segmentation Cavity’ of the Egg of the Frog.
Authors: Meek Alexander
Published: April 2021

The egg of the frog, Rana temporaria, starts its career of segmentation as does that of Amphioxus, but after the onecelled blastula stage a delamination of cells takes place, with the result that the wall becomes multicellular. The cavity is excentrally situated, the anterior wall being thin and the posterior wall thick. The latter consists of endoderm, and while internally it is impossible to point to a distinct demarcation between ectoderm and endoderm, externally an equatorial zone is defined which marks the limits of ectoderm and endoderm, and this is emphasized when the zone becomes a ring of proliferation indicating the beginning of the activities of the blastopore. The proliferation is followed by the appearance of a dorsal groove, the dorsal lip of the blastopore. An invagination takes place, confined, however, to the dorsal aspect of the embryo, and a horizontal slit-like cavity is produced which penetrates anteriorly above the segmentation cavity and is extended posteriorly as the dorsal lip of the blastopore advances over the large cells of the yolk-plug. This cavity is the enteron, and while it is forming the original cavity, which is still called the segmentation cavity, acquires a cup shape, the anterior wall being definitely resolved into ectoderm, and the endodermal margin of the cup gradually narrows and ultimately fuses, so that the cavity becomes enclosed in endoderm. It is almost universally believed that the segmentation cavity is compressed by the expanding enteron and that it finally disappears antero-ventrally in the endoderm. But A. M. Marshall, 0, Schulze, and 0. Hertwig have all drawn attention to cases of fusion between the two cavities, cases which indicate that sometimes the segmentation cavity may become converted into the forward part of the enteron. Such have been regarded as abnormal, and upholders of the orthodox view of the procedure which takes place within the egg of the frog explain them as being due to faulty preservation or preparation. On the other hand, the accepted view is not supported by a convincing series of figures. A stage is shown which presents the segmentation cavity and the enteron. The next stage is one which displays the enteron occupying the place of the segmentation cavity and the latter as non-existent or as a small cavity of the endoderm ventral to the enteron. Even if such a change actually takes place it is plain that the subsequent excavation and thinning of the ventral and lateral walls of the endoderm restores the cavity to the enteron, and the process could be explained as a variation of that produced by an earlier fusion of the two cavities. With this in mind it may be said, to begin with, that, if the segmentation cavity sometimes produces the anterior part of the enteron and usually disappears as a cavity enclosed by endoderm, the nomenclature of the cavity is wrong and misleading.
On Golgi’s Internal Apparatus in spontaneously absorbing Tumour Cells.1
Authors: Da Fano C.
Published: April 2021

In continuation of previous work the behaviour of Golgi’s apparatus during spontaneous absorption of transplantable tumours of the mouse is described. In some of them the apparatus soon becomes transformed into a granular almost structureless material ; in others this terminal phase is reached through stages which are probably determined by the characteristic structure exhibited by the apparatus in the healthy cells of the corresponding tumours. The modifications of the apparatus during such stages have a striking resemblance with the changes observed in different tissues under various physiological conditions. The connective-tissue cells, which invade the tumours as they are absorbed, are provided with a small, irregular, and sometimes reticular apparatus which is identical with that described by other authors in similar elements though in different pathological processes. In some of these elements the apparatus undergoes changes not altogether different from those observed in absorbing tumour cells. In general, the fragmentation of the apparatus begins when other cell constituents are still apparently unaltered, but its fragments seem to possess a great power of resistance to degenerative conditions.
On the Epithelial Fibres in the Skin of Mammals
Authors: Shapiro Boris
Published: April 2021

The structure of the epidermis is cellular, the syncytial theory of Frieboes being in disagreement with the histological, embryological, and physiological evidence. Two independent types of fibres—i nt r a cellular (Ereidesms) and intercellular (Deinop or es)—are present in the epidermis. The Ereidesms are elaborated by the cytoplasm of the epidermal cells. They are distributed in strict accordance with the laws of mechanics, their direction in any cell being that of the resultant of all mechanical forces acting on the cell. The function of the Ereidesms is that of a supporting tissue. The intercellular fibres (i. e. Deinopores) are ramifications of the undifferentiated cytoplasm of the epidermal cells, binding these elements together. Their distribution—in contrast with the intracellular fibres—is in nowise due to the mechanical forces acting on the cells. The function of the intercellular fibres is probably nutritive, their presence being due to the lack of blood-vessels in the epidermis. All Deinopores (i. e. bridges) without exception bear nodes. No definite conclusion, however, has been reached with regard to their significance.
The Prootic Somites of Heterodontus and of Amia
Authors: Beer G. R. de
Published: April 2021

The external rectus of Heterodontus is not partly composed of the mandibular somite. The only prootic somite recognizable as such in Amia is the premandibular. The muscles representing the mandibular and hyoid somites arise from mesenchyme in Amia. The relations of the eye-muscles to the optic nerve and the distribution of the oculomotor differ in Amia and Heterodontus.
Studies on the Vertebrate Head: Part I. Fish
Authors: Beer G. R. de
Published: April 2021

In a paper of this nature it is difficult to epitomize the results any more briefly than has been done in the actual text. Only a few of the more important conclusions will be summarized. The vena capitis medialis is the primitive head vein. It is replaced by the vena capitis lateralis by different methods in the different groups.The relations of the efferent pseudobranchial artery to the trabecula cranii differ in Selachians and the remaining Craniates. This may be explained by vessel-looping in the Selachian or by the different relations of the polar cartilage.The relations of the hyomandibular to the veins, hyomandibular muscle, and facial nerve in the different groups suggest that the hyomandibular (i) of Selachians is a true hyomandibular, (ii) of Teleosts and Amia a compound of an interarcual cartilage and a processus oticus hyomandibularis, the latter being a modified extra-hyal.The schematic condition of the true hyomandibular with the processus oticus hyomandibularis is shadowed in Ceratodus, embryonic stages.A certain number of constant relations exist, as set forth on p. 328.
Foettingeria actiniarum (parasitic in Anemones)
Authors: Morgan W. De
Published: April 2021

Claparède discovered this ciliate in the coelenteron of Actinia mesembryanthemum, and gave a short description of it (1) in 1863 under the name of Plagiotoma actiniarum. In 1880 Jourdan found it in Actinia equina, and added a short note and good drawing of it to his description of the anemone (2). Caullery and Mesnil (3) obtained it from Anemonia sulcata, Actinia equina, and Tealia crassicornis, describing it as Foettingeria actiniarum, n.g., and in addition to a general account of the parasite made some observations on the structure of the nucleus, on which Claparède and Jourdan had offered no opinion.
The Early Development of the Cat (Fells domestica)
Authors: Hill J. P. , Tribe Margaret
Published: April 2021

Our knowledge of the early development of the Cat, as indeed of the Carnivora in general, is singularly incomplete. Th. L. W. Bischoff, in his classical monograph ‘Entwicklungs-geschichte des Hunde-Eies ‘published in 1845, provided the first account of the development of a Carnivore from the unsegmented egg onwards and, considering the date of his work, his achievement was really a remarkable one. In addition to later embryonic stages, he described and figured a series of segmenting ova and blastocysts of the Dog, with such fidelity and accuracy that his account is, even to-day, of the greatest interest and value. He recognized and figured the germinal vesicle of the full-grown ovarian ovum and the refractive granules (‘Dotter ‘) present in the cytoplasm of the latter. He observed the persistence of part of the discus proligerus round the unsegmented tubal egg, and noted its thick zona and the numerous sperm-heads imbedded in it. He figured the two-celled egg with what are evidently two polar bodies situated in the plane of cleavage. He described and figured the three-celled and four-celled stages, his figures of the latter showing quite accurately the characteristic crossshaped arrangement of the blastomeres. He figured three later tubal eggs, said to be composed of eight, ten, and eighteen blastomeres respectively, and he also illustrated and described a series of morulae and blastocysts from the uterus. He recognized the delicate membranous wall of the blastocyst lying inside the zona and also ‘den runden und gleichmassig dunkeln Fruchthof ‘, and since he found that the latter is situated in the former, he termed this vesicular stage ‘ die Keimblase ‘.
The Growth of the Egg in the Dab (Pleuronectos limanda)
Authors: Wheeler J. F. G.
Published: April 2021

A Study of the literature of intraovarian development leaves no doubt that the same fundamental process in various animals differs considerably in its cytological details. It seems impossible to draw up a general plan of the’ sequence of events leading to the maturing and shedding of the egg even in a group of related animals.
The Chromosomes of Paris quadrifolia and the Mechanism of their Division
Authors: Lee Arthur Bolles
Published: April 2021

This subject has already been treated of by the present writer in a paper entitled “La Structure des Chromosomes et du Noyau au repos chez Paris quadrifolia” in ‘La Cellule’, tom. xxviii. 2, 1913. It was there concluded that the chromosomes in question consist of a chromatic cylinder which, at certain stages, is alveolated, as described by Gregoire and his pupils, and not furnished with the enveloping spiral fibre described by Baranecki and by Bonnevie. It was also concluded—dubiously—that their longitudinal division is brought about by the confluence into a single axial lumen of a row of alveoles formed in them during the prophase—the chromosomes splitting along this lumen. But it was not clear how the existence of this axial lumen could bring about the division of the cylindrical chromosome into two equal daughter cylinders.
Notes on Planaria vitta Dugès
Authors: Ullyott P.
Published: April 2021

Specimens of a white planarian found in springs and streams in the Lake District were examined in the Laboratory at Wray Castle, Westmorland. Later, observations were made in Wales on the same species, and collections made for subsequent examination. Numerous animals from both localities have been cut into serial sections, and have been identified as P1 a n a r i a vitta Dugès.
Cytoplasmic Inclusions in the Eggs of certain Indian Snakes
Authors: Lal Krishna Behari
Published: April 2021

1. Golgi bodies are juxtanuclear in the early stages after which they migrate towards the cortex, getting finally dispersed in the cytoplasm. Some of the elements in the early stages swell up and become round; this stage is followed by the formation of fatty-yolk bodies. In general the individual Golgi elements have a lightly staining centre surrounded by a heavily impregnated rim. Sometimes they also appear as crescents in section. These bodies are also present in the theca and the follicle cells of the oocyte and periodically ‘infiltrate’ inwards into the cortical region.

2. Mitochondria are feebly developed, and whenever met with are granular in early stages and dust-like and more peripheral in advanced oocytes.

3. Fatty yolk is short-lived and is formed in the cytoplasm under the influence of a number of Golgi bodies.

4. Albuminous yolk appears late in the development of the oocyte. It arises in the cytoplasm, sometimes in vesicles and sometimes in association with mitochondria in the peripheral region.

5. The four species of snake examined, Zamenis mucosus, Gongylophis conicus, Tropidonotus stolatus, and Tropidonotus piscator, are not very dissimilar with regard to the origin and behaviour of their cytoplasmic inclusions.
The Early Development of the Nephridia in Amphioxus: Introduction and Part I, Hatschek’s Nephridium
Authors: Goodrich Edwin S.
Published: April 2021

It is now some thirty years since I first undertook the study of “the development of the excretory organs of Amphioxus (Branchiostoma lanceolatum, Pallas). When it was discovered (Goodrich, 1902) that Amphioxus is provided with nephridia of essentially the same structure as the solenocytebearing protonephridia of various Polychaetes and other Invertebrates it became a matter of interest to find out how they are developed. Yet, so far as I am aware, only one author has attempted to give a detailed account of their early development in two short papers (R. Legros, 1909 and 1910). In 1909 I described the nephridia in larval stages, and since then from time to time, as opportunity offered, I have tried to make out their early development and their first origin. The investigator of this problem is confronted with many difficulties. The material is hard to obtain, difficult to preserve satisfactorily, and particularly difficult to stain well. After trying various well-known fixatives, a mixture of corrosive-acetic and picro-nitric for embryonic and Bouin’s fluid for larval stages were found to give the best results. It is essential to anaesthetize the later larvae before fixation to prevent muscular contraction. Borax-carmine and picro-nigrosin, Heidenhain’s iron-haematoxylin and eosin or light-green, and Mann’s methyl-blue and eosin are the most satisfactory stains. The cells are so small and their derivation so difficult to make out that sections of more than about 3 or 4 p in thickness are almost useless. The observations recorded below on embryonic stages were made on material provided by the Zoological Station at Naples for which I here express my gratitude. The larval material was preserved by me at Faro, at Naples, and in Heligoland. I have also to thank the authorities of the Biologisches Anstalt in Heligoland for sending me preserved larvae by post.
Oligochaeta from Sarawak.
Authors: Michaelsen W.
Published: April 2021

I Regard the opportunity to study the Oligochaeta collected by the members of the Oxford University Expedition to Sarawak as a bequest of my late colleague and friend Dr. John Stephenson, London. He would have been more competent to do this work, but fate has taken him prematurely from his work-table. I shall dedicate the first new species of the present collection to the manes of our dear late colleague, who will never die in the memory of his fellow-workers, and whose scientific work will endure as long as men devote themselves to our special science.
On Kibisidytes marinus, n.gen., n.sp., and some other Rhizopod Protozoa found on surface films
Authors: Jepps Margaret W.
Published: April 2021

The observations set out in this paper began with the finding of small brown-shelled organisms with pseudopodia on coverslips left in marine aquaria1 for other purposes. The same were discovered later on the surface film. My attention was caught because at first sight they looked like testacean rhizopods, of which none, so far as I know, have ever been recorded from the sea. When similar forms were found in fresh water the interest deepened and further study led to the recognition of several distinct organisms already known to science in fresh water, and a previously undescribed form in the sea.
The Biology and Development of Cryptochaetum grandicorne (Diptera), an Internal Parasite of Guerinia serratulae (Coccidae)
Authors: Thorpe W. H.
Published: April 2021

In a previous paper was described the life-history of Cryptochaetum iceryae parasitic on Icerya purch as i, an Australian species introduced into California. It was shown that the genus is highly specialized for life as a parasite, and that it represents a separate and restricted line of evolution of parasitic habits among insects. The present study concerns Cryptochaetum grandicorne which is probably confined to the Mediterranean region, and which is the only species of the genus known to occur in Europe. The two species show notable differences in structure and life-history although both are highly adapted to a parasitic mode of life. The very minute eggs are laid in the haemocoel of the host. The egg hatches to form a short-lived ‘embryo-larva ‘at first atracheate and showing no trace of external segmentation. Mouth parts are present although the fore-gut is closed, food materials presumably being absorbed by diffusion from the blood of the host. The second stage larva is tracheate but apneustic. Segmentation is complete. The fore-gut is now open but the hindgut remains closed. The food consists of the blood and fat-body of the host. The third stage larva is omnivorous devouring the internal organs of the host indiscriminately and the hind-gut is open. The tracheal system is amphipneustic. A few days after the commencement of the instar the posterior spiracles pierce the skin of the host and establish connexion with the atmospheric air. The puparium is formed within the dead body of the host. Asin Cryptochaetum iceryae the larva is supplied with a pair of long tubular caudal filaments, lobes of the bodywall containing blood and tracheae, which arise from the posterior segment and ramify among the organs of the host. Experiments indicate that they serve to increase the surface area available for respiratory exchange between the larva and the blood of the host. They are also readily permeable to water. Although a large number of eggs may be placed within a single host, only one reaches maturity. The highly specialized ovipositor is described in detail since it appears to be a striking adaptation to a parasitic mode of life, and cannot be derived directly from the rasping ovipositor of the Agromyzidae. In South Italy as in South France there is one generation per year, the life-history of the parasite being closely correlated with that of the host. Special attention is paid to those features in which grandicorne differs from iceryae and the significance of these differences is discussed.
The Origin and Nature of the Nucleolus
Authors: Gardiner Mary S.
Published: April 2021

Cytologists whose investigations have been concerned with the nucleolus have either regarded it as related to the formation of the chromosomes, or as connected actively or passively with cellular metabolism. Montgomery (1898), Ludford (1922), Wilson (1924), Fikry (1930), and Sharp (1926 and 1934) have all presented comprehensive reviews of these investigations which show little agreement in the interpretation of nucleolar function. Those investigators who relate it to chromosome formation differ among themselves in regarding the connexion either as a direct one, the nucleolus representing an active agent in the elaboration of chromatin, or as an indirect one, the nucleolus contributing non-chromatinic material to the chromosomes. Those who support the metabolic view also disagree in believing, on the one hand, that the nucleolus is an active agent in the vital processes of the cell, and on the other hand, that it is ergastic in nature, composed either of waste products of the cell’s metabolism, or of material to be used in the manufacture of specific cell products.
Mouth and Anus
Authors: Goodrich Edwin S.
Published: April 2021

Embryologists and more especially those zoologists who are engaged in teaching must long have felt that there is some confusion, or at least want of precision, in the use of the word mouth. Sometimes it is used to mean simply the anterior opening of the alimentary canal; at other times a more special morphological significance is attached to it, and the term is used to denote the anterior opening leading from the ectodermal stomodaeum into the endodermal cavity or enteron.
Ultra-Centrifuging the Spermatocytes of Helix aspersa
Authors: Beams H.W. , Bronte Gatenby J. , Muliyil J.A.
Published: April 2021

In the spermatocyte of Helix, as in the guinea-pig uterine gland cells and in the root-tip cells of the bean, the Golgi bodies pass centripetally whereas the mitochondria pass centrifugally when ‘ultra-centrifuged’.
Studies on the Cytoplasmic Components in Fertilization : I. Ascaris suilla
Authors: Collier Vines
Published: April 2021

This study of the cytoplasmic components was done on the fertilized eggs of Ascaris suilla. This species of Ascaris is found in the intestinal tract of the common domestic hog and is identical morphologically with Ascaris lumbricoides, the roundworm found in man. It has been proved conclusively by several of the Japanese workers that although Ascaris suilla is morphologically identical with Ascaris lumbricoides, it is physiologically a distinct species in that Ascaris suilla will not live in the medium of the human intestine, and Ascaris lumbricoides will not live and grow in the intestine of the hog.
The Innervation of the Adrenal Glands of Mammals; a Contribution to the Study of Nerve-endings
Authors: Willard Dorothy M.
Published: April 2021

The cells of the adrenal cortex of the cavy and mouse are sometimes innervated directly by nerve-fibres passing over and around the cells, but such nerve-fibres are very scarce in the cortex, the majority of whose cells are probably not under nervous influence. There is a complex plexus of nerve-fibres among the cells of the adrenal medulla, the fibres of the plexus coming into close contact with the surface of the chromophil cells, but never penetrating inside them. Formations comparable with the boutons de passage and the boutons terminaux of the central nervous system occur in this plexus. However, the average number of boutons of both sorts per fifty medullary cells was found to be only 1-8 in young guinea-pigs, and 1 -4 in adults. It is, therefore, concluded that they do not represent the main agent by which the secretory cells are activated, but that this function is performed by the nervous impulse passing in the network of fibres around the cell.
The function of the Corpus Allatum in the Growth and Reproduction of Rhodnius prolixus (Hemiptera)
Authors: Wigglesworth V. B.
Published: April 2021

During its growth Rhodnius prolixus moults five times. At the first four ecdyses its characters change comparatively little; but at the final ecdysis, when the insect becomes adult, it undergoes a definite ‘metamorphosis’. In an earlier paper (Wigglesworth, 1934) it was shown that the initiation of each moult and the prevention of metamorphosis until the final moult are both effected by hormones circulating in the blood. It was suggested that two factors are involved: a ‘moulting hormone ‘which initiates cell division in the epidermis, and an ‘inhibitory hormone ‘which prevents the development of adult characters until the insect is full grown. For purposes of description this hypothesis of two active substances will be retained; although, as previously pointed out, it may ultimately be proved that a single substance in different concentrations is responsible for both effects.
On the Ciliary Mechanisms and Interrelationships of Lamellibranchs: PART II: Sorting Devices on the Gills
Authors: Atkins Daphne
Published: April 2021

Some sorting devices on the gills of Lamellibranchs are described. These are: Utilization of plicae for sorting in two ways; the one (a) in which the frontal currents are in opposite directions in the grooves and on the crests, and particles intended for consumption are carried in the grooves to the safe dorsal channels, e.g. in Pecten; and the other (b) in which the plical grooves open into the safe channel at the bottom of the deep marginal food groove, while the crests lead to a superficial path along the lobes of the marginal groove, e.g. in Pinna.The deep marginal groove of the demibranchs of certain bivalves is able to open and close, thus accepting or rejecting material carried to it by the frontal cilia of the filaments, e.g. Solecurtus scopula.Certain Lamellibranchs have fan-shaped groups of long cilia on the lobes of the marginal groove of the demibranchs, which prevent the entry of large particles or collections of particles, but allow that of small ones, e.g. Musculus marmoratus.In certain bivalves long, stout frontal cilia are found in addition to the usual short, fine ones. The cirrus-like cilia most probably function in the removal of grains of sand and rock from the gills, e.g. Mactra corallina, Barnea parva.

Small gills and large palps are characteristic of certain deposit feeding bivalves with long free siphons, and the presence of large, cirrus-like cilia on the posterior region of the gills beating obliquely forward, provide additional help to draw the current down the long inhalent siphon.

Certain of the ciliary structures described in this paper are clearly adaptive, correlated with feeding difficulties incidental to the habitat. Fine guarding cilia appear to be frequently correlated with the presence of a certain amount of mud or silt in the soil; they are presumably efficient in dealing with the particles of a muddy soil, but not sufficiently robust when mainly coarse material has to be dealt with. A correlation of cirrus-like cilia with sand dwelling and rock and wood boring habits has been observed.

It will be evident from the observations recorded in this paper that a preliminary sorting of material on the gills before it is passed on to the palps is far from unusual in Lamellibranchs. Further research will most probably add other examples.
On the Ciliary Mechanisms and Interrelationships of Lamellibranchs: PART III: Types of Lamellibranch Gills and their Food Currents
Authors: Atkins Daphne
Published: April 2021

Seven main types of Lamellibranch gills and their food currents, together with a number of varieties, have been described. These are shown summarily and comprehensively in the composite diagram in Text-fig. 18.
The Structure and Development of the Tail in the Plaice (Pleuronectos Platessa) and the Cod (Gadus Morrhua)
Authors: Barrington E. J. W.
Published: April 2021

The structure and development of the tails of Pleuronectes platessa L. and of Gadus morrhua L. are described, with some reference to Gadus merlangus L. In Pleuronectes: (a) seven hypural cartilages are identified, the most posterior becoming a dorsal element in the definitive tail while the next three fuse to form the upper of the two hypural bones borne by the terminal vertebra; (b) the penultimate vertebra comes to bear two dorsal and two ventral arches, probably basalia, as a result of their fusion during development; (c) the last neural and haemal arch bear traces of transient interbasalia at their first appearance. In Gadus: (a) the tail resembles that of Pleuronectes in certain respects, including the general arrangement of the dorsal and ventral skeletal elements, the appearance of transient interbasalia in connexion with the last neural and haemal arch, and the fusion of two dorsal and ventral arches, although these come to be borne by the ante-penultimate vertebra instead of by the penultimate vertebra; (b) the embryonic axial lobe of the fin is median (instead of dorsal as it is in Pleuronectes) as a result of the upper half of the definitive fin being formed by the backgrowth of a dorsal fin-fold. The two types of fin are compared, and it is concluded that the Gadoid fin could have been derived by the fusion of a homocercal fin, of a type more primitive than that of Pleuronectes, with a dorsal and ventral fin-fold, accompanied by the loss of the most terminal of the hypurals characteristic of the normal homocercal fin.