bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Ultra-centrifuging the Oocytes of Lumbricus terrestris
Authors: Norminton Gertrude M.
Published: April 2021

The ultra-centrifuged cell becomes stratified into fourlayers: fat, cytoplasm containing the nucleus and Golgi bodies, mitochondria, and a clear substance. The fairly large spherical, greyish bodies seen in the living oocytes of Lumbricus are fat, not Golgi bodies. This fat contains cholesterol. The Golgi bodies are slightly curved, or straight rods, found, in the ultra-centrifuged cell, in a layer placed centrifugally to the nucleus. The neutral-red granules are artifacts. If centrifuged they collect beside and beyond the nucleus. The mitochondria are granular and may become alined into chains. The heaviest substance in the cell is probably a fluid.
On the Histology of the Skin of the Lungfish Protopterus annectens after experimentally induced Aestivation
Authors: Smith G. M. , Coates G. W.
Published: April 2021

During the past year observations have been made on the histological structure of the skin of two lungfishes (Protopterus annectens Owen) kept for a period of almost six months under conditions of aestivation induced experimentally at the New York Aquarium. Both lungfishes had been caught in the fresh-water marshes near Beira, East Africa, and shipped directly to New York. They were adult fishes and measured approximately 14 inches in length.
On the Protozoan Parasites of Calanus finmarchicus in the Clyde Sea Area
Authors: Jepps Margaret W.
Published: April 2021

An account is given of the parasites reputed to be of protozoan nature which were observed in Calanus finmarchicus in the Clyde Sea Area, during the years 1933 to 1936. These comprise Blastodinium, Syndinium, some Gregarines, an ectoparasitic Ciliate new to science, Paradinium, Ellobiopsis, and Ichthyosporidium, besides early stages in the development of some Platyhelminth worms.

A special study is made of Paradinium, which was plentiful throughout the summer months, and of the effect of the plasmodial parasites on their hosts.
Remarks on the New Nineteen-Band Test-Plate of Nobert
Authors: Woodward J. J.
Published: April 2021

In comparing the various object-glasses belonging to the microscopical section of the Army Medical Museum, the test plate of Nobert has been much employed recently as the most accurate means of determining defining power. The plate used was one of the nineteen-band plates most recently furnished by Nobert; and its use for the purpose indicated has led the writer to a somewhat detailed study of the plate itself.
The Structure and Development of Wax Glands of Pseudococcus maritimus (Homoptera, Coccidae)
Authors: Pollister Priscilla Frew
Published: April 2021

The females of Pseudococcus maritimus have three types of multicellular wax-glands, one with a triangular external pore, another opening through a long tube, and a third with a multilocular aperture. The first two are widely distributed on all surfaces of the adult. The third is restricted to the ventral surfaces of the last five segments. This multilocular type is found only in the adult. The triangular glands are found at all stages and these structures progressively increase in number with each successive instar. The tubular type appears first in the second instar; the number is reduced in the third instar; and in the adult it is again increased to the largest number found at any stage.

The three glands are all modifications of one general plan of histological structure. The glandular elements are sub-epidermal cells arranged in a ring of peripheral cells surrounding a single central cell. There are three peripheral cells in the triangular gland and ten in each of the others. The peripheral cells are uninucleate and contain vacuoles of secretory material. The central cell of the tubular and triangular glands has a large and two small nuclei and contains a large reservoir, from which a chitinized duct system leads to the gland-pore. The central cell of the multilocular gland is small and relatively undifferentiated. The author favours the view of Šulc that the wax is probably secreted by the peripheral cells, while the central cell secretes a substance that causes the wax filaments to adhere to form large cylinders.

The glands are developed by cell-multiplication from the epidermis at the time when it is freed from the cuticula at the beginning of ecdysis. After the initial period of cell-multiplication the first differentiation is the development of the external pore within the neck-cell. Later in the development of multilocular glands it is believed the glandular cells grow through the neck-cell to establish the functional relationship with the pore. It is suggested that this is analogous to the relationship between tormogen cell and trichogen cell in the development of a spine.
On the Spinal Nerves of the Myxinoidea
Authors: Goodrich Edwin S.
Published: April 2021

The spinal nerve in the Gnathostomata is of mixed function, being formed by the junction of a mainly sensory dorsal root, provided with a ganglion, with a ventral motor root. The mixed nerve passes outwards posteriorly to the myomere supplied by its ventral root. Intersegmental arteries run dorsally from the dorsal aorta between the successive myomeres, and each artery passes up posteriorly to the spinal nerve. Segmental nerves and intersegmental arteries therefore alternate. These fundamental relations, illustrated in Text-fig. 1, are constant from fish to man, and can be seen in embryonic stages (Goodrich, 1930); but they may be modified in the adult.
On the Ciliary Mechanisms and Interrelationship of Lamellibranchs: PART VI. The Pattern of the Lateral Ciliated Cells of the Gill Filaments of the Lamellibranchia
Authors: Atkins Daphne
Published: April 2021

The pattern of the lateral ciliated cells of the gill filaments has been examined in a number of Lamellibranchs and figures given, In the Protobranchia the lateral ciliated cells, except for a row on the abfrontal side, have no definite shape or arrangement; in the higher Lamellibranchs there is an orderly arrangement of the approximately rhomboidal cells in rows. The arrangement of the cells in any species appears to be constant. In the group possessing micro-latero-frontal cilia the variation in the pattern of the lateral ciliated cells in the various families is in marked contrast with the constancy of the general type of pattern found in the majority of the Eulamellibranchs.
On the Anatomy of Cercaria Macrocerca from Sphaerium Corneum.
Authors: Vickers G. G.
Published: April 2021

A detailed anatomical description is given of the sporocyst and cercaria of Cercaria macrocerca (Fit) from the gills of Sphaerium eorneum (Linn.).

The development of the large cells surrounding the excretory vesicle of the cercaria is described. It has been found that the granules with which these cells are packed originate round the nucleus and afterwards migrate towards the lumen of the vesicle. These granules do not appear to be discharged on encystment of the cercaria to act as cystogenous material ; they are shed gradually into the excretory vesicle, and it is therefore natural to suppose that they are granules of excretory material.

In heavy infestations the mechanical effect of large numbers of sporocysts between the gill lamellae of the host completely prevents reproduction of the mollusc. Cercariae escaping from the sporocysts continually rupture the gill lamellae of the host, and large areas of the gills are thus put out of action.
The Chromosomes of the Cymothoid Isopod Anilocra.
Authors: Callan H. G.
Published: April 2021

Anilocra mediterránea has a diploid chromosome number of twelve, eight of the chromosomes having median, and four subterminal centromeres.

The localization of chiasmata is extreme and is of a previously undescribed type, combining the terminal and centric systems.

The centromeres stain differentially from the non-centric regions of the chromosomes ; they are the only parts stained at anaphase of first meiosis, and at metaphase and anaphase of second meiosis.
The Enteronephric Type of Nephridial System in the Genus Tonoscolex (Gates)
Authors: Bahl Karm Narayan
Published: April 2021

The ‘enteronephric’ type of nephridial system, previously described by the author in Pheretima, Lampito, and Woodwardiella (Nellogaster), has now been shown to characterize the genus Tonoscolex as well. It seems that this type of excretory system is widely distributed in the subfamily Megascolecinae. The nephridia are of three kinds: the enteronephric septal nephridia, the exonephric integumentary nephridia, and the enteronephric pharyngeal nephridia. There are twenty-four to thirty séptal nephridia in each of those segments where they are best developed, these nephridia being much larger in size than the septal micronephridia of Pheretima. The pharyngeal nephridia form a cylindrical bunch around the oesophagus in the sixth segment and open into the pharynx in front by a large number of ducts. The integumentary nephridia are extremely minute and open singly on the body-wall. The elaborate system of septal excretory canals and supra-intestinal ducts characteristic of the septal nephridial systems of Pheretima, Lampito, and Woodwardiella, does not exist in Tonoscolex. The system in Tonoscolex is therefore much simpler and probably more primitive, and may represent an intermediate stage between the purely exonephric meganephridia ofLumbricus and the elaborate enteronephric system of Pheretima, Lampito, and Woodwardiella.
Cytology of Human Uterine Glands in Gravid and Non-Gravid Phases
Authors: Aykroyd Olive E. , Gatenby J. Brontë
Published: April 2021

After menstruation the basalis regions of the uterine glands alone persist. The columnar cells evacuate most of their granular contents, and the Golgi apparatus loosens out and breaks up. (Text-fig. 3 A.) The postmenstrual cells are cubical limpid cells, with a Golgi apparatus consisting of a few granules arranged in a line. (Text-fig. 3 B.) In the proliferative phase the Golgi apparatus re-forms and grows into a characteristic net. The cells become columnar. No marked aggregation of granules has as yet occurred. In the progravid phase, the cells become cubical, the Golgi apparatus spreads, and a marked aggregation of fat and glycogen appears at the inner pole of each cell. (Text-fig. 3 C.) Should pregnancy supervene, the cells secrete numerous ovoid (proteid) granules at their outer poles (Text-fig. 3 D). These granules are topographically related to the outer edge of the Golgi apparatus. The presence of the granules in any specimen of curetting reveals that it has been recovered from a case of interrupted pregnancy. Exceptions to this might be those which are known to hold for the Ascheim-Zondek pregnancy test. The uterine glands contain only one type of secretory cell which may be ciliated or non-ciliated.
The Blood Systems of Sabella and Spirographis
Authors: Ewer D. W.
Published: April 2021

The anatomy of the blood system of Sabella pavonina is described. Differences from Sabella found in the structure of the blood system of the closely related Spirographis spallanzanii are pointed out. Very young Spirographis show no difference in the structure of the blood system from Sabella. Certain of the differences are, however, found in slightly larger specimens of Spirographis which are smaller than fully grown Sabella. The differences are therefore regarded as specifically significant. A preliminary account is given of the histology of the blood-vessels. The main longitudinal vessels show a distinct muscular layer, which is absent in circular and capillary vessels. The course of the circulation is described. An explanation of the mechanism of the sorting of oxygenated and deoxygenated blood is put forward. Peristalsis in the main longitudinal vessels occasionally reverses its direction ; there is thus no physiological polarization of the direction of peristalsis. The occurrence of blind-ending vascular structures in other polychaetes is reviewed and suggestions put forward concerning their function.
A Study of the Cytoplasmic Inclusions during Maturation, Fertilization and the First Cleavage Division of the Egg of the Mouse
Authors: Gresson R. A. R.
Published: April 2021

1. Ova of the mouse were fixed at times varying from 5 to 43 hours after copulation.

2. Ovulation may take place at either the stage of the first or the second maturation division.

3. The sperm enters the egg during the anaphase of the second maturation division. As indicated by one egg the sperm may occasionally enter during the first division. The second maturation division takes place between 5 to about 7 hours after pairing. The stage of the pronuclei may be reached at about 6 hours after pairing, but usually is not reached until later. The first cleavage division takes place between 21 and 28 hours.

4. During the maturation divisions the yolk-globules are most numerous in the half of the egg opposite to that at which the divisions are taking place. The mitochondria are granular and are collected into small clumps ; a few, chiefly towards the periphery, are scattered singly through the cytoplasm. They are most numerous in the central region. During the first division, and in the early stages of the second division, they are numerous around the spindle. Few mitochondria are eliminated in the polar bodies. The Golgi elements are in the form of granules and of small irregularly shaped bodies; they are fairly evenly distributed through the cytoplasm.

5. During the stage of the pronuclei the distribution of the yolk-globules is similar to that during the polar divisions. In the later phases there is a concentration of the mitochondria in the neighbourhood of the pronuclei. The Golgi elements are scattered through the cytoplasm; they increase in size and undergo fragmentation.

6. The mitochondria become arranged around the spindle of the first cleavage division and are transmitted with approximate equality between the first two blastomeres. The Golgi elements remain scattered through the cytoplasm but are slightly more numerous in the neighbourhood of the zygote nucleus. The Golgi elements and the yolk-globules are fairly evenly distributed between the first two blastomeres.

7. The middle-piece of the sperm is carried into the egg. The mitochondria of the sheath are, at first, larger than those of the egg ; they spread out through the cytoplasm and undergo fragmentation. It is concluded that the mitochondria of the sperm are transmitted to the first two blastomeres. There is evidence that the Golgi elements of the middle-piece fragment and that the individual elements become scattered through the ooplasm before the first cleavage division.

8. Granular mitochondria are present in the blastomeres of the two-cell stage ; they are collected into small clumps and are scattered singly through the cytoplasm. The Golgi elements undergo fragmentation; they are fairly evenly distributed throughout the cytoplasm.
Abdominal Appendages of Asellus, II
Authors: Needham A. E.
Published: April 2021

1. The anterior abdominal appendages of A. meridianus, while showing fundamental similarity to those of A. aquaticus, show considerable differences in structure, function, and development.

2. Neither species shows a complete superiority over the other in respect of these differences, nor is there as yet reliable evidence from experiment or from observations on distribution as to their relative viability.

3. The evidence from development in sum indicates that the A. meridianus group is the more primitive, the A. aquaticus type recapitulating an A. meridianus stage. Both groups have, however, evolved considerably since their first divergence, the changes affecting all stages of ontogeny; in respect of one species difference in particular, A. meridianus shows overstepping of the A. aquaticus condition which is primitive.

4. In the male A. meridianus there is considerable functional transposition between parts of the system as compared with A. aquaticus.

5. The developmental studies indicate further: (1) the extreme regularity of the processes, even to the smallest detail ; (2) the independence of growth and development on periodicity in moulting; (3) methods of addition of setae during development.

6. In the light of these studies the female intersexes of Maercks (1931) are seen to correspond to stages in normal male ontogeny, but with asynchronizations between parts of the appendages.

7. The intersex of Unwin (1920) may have been a species hybrid. He was working with A. meridianus, rather than with A. aquaticus as he believed.

8. A case of compound heteromorphosis affecting the anterior abdominal appendages of A. meridianus is described, and the importance of the peripheral motor nerves in the determination of the phenomenon is indicated.

9. Regeneration in these appendages may be quite normal, when it shows an accelerated recapitulation of ontogeny. It may be abnormal in showing lack of synchronization between parts, or even complete suppression of some. The rate of regeneration increases with age up to a point, and then decreases. It also decreases with the amount of an appendage removed.

10. Relative independence and lack of synchronization between parts is thus seen in intersexes, in other abnormalities, and in regeneration, and in all cases may depend on peripheral motor nerves.

11. Chains of sense cells and hollow chitinous ingrowths associated with them are attached to the base of many of the setae in Asellus.
The ‘Dorsal Organ’ of Collembolan Embryos
Authors: Tiegs O. W.
Published: April 2021

Our present knowledge of the problematical ‘dorsal organ’ of Collembolan embryos is based mainly on the writings of Uljanin (1875), Lemoine (1883), Wheeler (1893), Claypole (1898), Uzel (1898), and Philiptschenko (1912). Owing to the minute size of the embryos of most Collembola much difficulty has been experienced in making accurate observations on its structure ; only in the work of Claypole and of Philiptschenko have actual sections been employed for the purpose.
Ciliary Currents in the Mantle Cavity of the Atlantidae
Authors: Yonge C. M.
Published: April 2021

The ciliary currents in the mantle cavity of the Heteropod, Oxygyrus, were examined in the intact animal. The presence of three sets of currents concerned with the rejection of sediment, already postulated from examination, after dissection, of the mantle cavity in other Prosobranchs, was confirmed. The great majority of the sediment brought in with the respiratory current impinges on the line of the osphradium. This favours the conclusion that this organ is tactile in function and not a chemoreceptor. The extent to which the organs and currents in the mantle cavity are modified as a result of pelagic life is discussed.
The Nature and Formation, of the Spermatophore and Sperm Plug in Carolnus Maenas.
Authors: F. Spalding J.
Published: April 2021

1. The structure of the male reproductive system of Carcinus is described with special reference to the region of formation of the spermatophores and the anatomy of the intromittent organ.

2. The vas deferens produces two fluids, one of these is probably chitin in a fluid form, whilst the other is similar in some respects to the substance forming the general body cuticle, i.e. protein. This substance forms the capsule of the spermatophore.

3. The intromittent organ consists of the modified first and second pleopods and is richly supplied with rosette glands similar to those producing the body cuticle. The ducts of these glands open into the cavity of the first pleopod and their secretion could easily pass with the seminal fluid into the female crab.

4. The female reproductive system is described with special reference to the spermatheca and the cyclical changes occurring in this organ.

5. The sperm plug is composed of two parts distinguishable by their staining reactions. One is similar to the cuticle in its general properties and is probably the product of the rosette glands in the male pleopod. The other is probably chitin formed from its fluid precursor in the seminal fluid of the male crab.

6. It is suggested that the spermatophore of the Brachyura is a degenerate structure having lost its main function, the protection of the sperms during the interval between copulation and egg-laying, in correlation with the development of the internal spermatheca and internal fertilization.
Denticles in fossil Actinopterygii.
Authors: S. Goodrich E.
Published: April 2021

It has long been known that true denticles, as opposed to mere ridges, tubercles, or spines of the outer ganoine layer may occur on the exposed surface of the scales and dermal bones of living Actinopterygii such as Poly pt er us orLepidosteus. But, so far as I know, they have never been described on the scales or dermal bones of any fossil Actinopterygian.1 This is a remarkable fact, for we should certainly expect to find them at all events in the more primitive forms.
Structure and Osmiophilic Inclusions of Astasia harrisii
Authors: Smyth J. D.
Published: April 2021

The general structure of Astasia harrisii Pringsheim is described. The osmiophil material is well shown in Weigl preparations and resists bleaching by hydrogen peroxide or turpentine. In many individuals it consists roughly of an oval mass connected to the reservoir by what is considered to be a canal with osmiophilic walls. The shape of this canal changes considerably, and in many specimens has a blebbed appearance. In others it consists of a number of small osmiophilic vacuoles placed end to end. A small vacuole is often present at the tip of the canal. In a few cases the reservoir is surrounded by an osmiophil cortex continuous with the walls of the canal. It is suggested that the osmiophil material possibly represents the homologue of the Golgi apparatus in higher forms, and is concerned with the secretion or excretion of some liquid down the canal into the reservoir. The possible evolution of the osmiophil material in Astasia is discussed.
Formation and Nature of the Opercular Chaetae of Sabellaria alveolata
Authors: Ebling F. J.
Published: April 2021

The structure of the operculum of Sabellaria alveolata L. is described. There are three fans of chaetae set in each opercular lobe. The chaetae are formed in two longitudinal sacs on each side ; the outer one supplying the outer fan, and the inner the two remaining fans. There is a continual movement of chaetae from the sacs into the dorsal ends of the fans ; they move round the fans and eventually drop out at the ventral ends. The chaetae are secreted by a continuous band of cells moving round the posterior end of the sac and forwards along its ventral side. The nature of the striations at the base of the forming chaeta is discussed. Around this primary core secreted by the basal cell, other cells of the sac secrete a secondary layer. The structure of the fully formed chaeta is described and its two layers correlated with those observed in process of formation. The chaetae are shown to be composed of protein and not chitin. The materials of the outer and inner layers appear to have different iso-electric points.
Studies on the Structure, Development, and Physiology of the Nephridia of Oligochaeta: Part V. The Enteronephric System in Mega-scolex ceylonicus and M. sarasinorum, with remarks on the Phagocytic Organs in Megascolex templetonianus
Authors: Bahl Karm Narayan
Published: April 2021

With the discovery of the enteronephric type of nephridial system in the earthworms Megascolex ceylonicus and Megascolex sarasinorum, this type of nephridial system is now known to occur in the following earthworms: Pheretima—all species. Lampito mauritii and Lampito trilobatus. Woodwardiella bahli. Tonoscolex —all species. Megascolex: (a) Megascolex cochinensis. (b) Megascolex konkanensis. (c) Megascolex ceylonicus. (d) Megascolex sarasinorum. Of these earthworms the best developed system is found in Pheretima, while the most primitive occurs in Megascolex ceylonicus and Megascolex sarasinorum. Megascolex templetonianus does not possess the enteronephric type of nephridial system. Like Acanthodrilus falclandicus, Megascolex templetonianus possesses a pair of well developed ventral phagocytic organs in each segment behind segment XIX, one on each side of the ventral nerve-cord.
Morphology of the Osmiophil Material of Rhabdomonas costata, and its Behaviour during Division
Authors: Smyth J. D.
Published: April 2021

In Rhabdomonas costata Pringsheim the osmiophil material, as shown in Weigl preparations, is very variable in amount and arrangement. In the majority of organisms it takes the form of a large osmiophil body lying beneath the reservoir, to which it appears to be connected by a short osmiophilic canal-like structure. Small scattered osmiophil granules are aggregated in the region of the reservoir and sparsely distributed throughout the cytoplasm. In some individuals the osmiophil ‘canal ‘is absent. The osmiophil body may also be present as a ring with a thickened osmiophil cortex and an osmiophobe centre. The behaviour of the osmiophil substance during division is as follows: the body loses its canal and spreads along the lower wall of the reservoir; as division proceeds it becomes divided into two masses, and when the organism separates into daughter individuals each monad contains nearly equal quantities of the osmiophil substance. There is thus a definite dictyo-kinesisin Rhabdomonas. In a few instances the osmiophil material is carried over whole to one of the two organisms formed by division. In some normal (non-dividing) individuals two osmiophil bodies and their respective canals are found. From the fact that the osmiophil material in Rhabdomonas is demonstrable after the metazoan Golgi Weigl technique, is resistant to bleaching, and is separated out evenly in most cases during division, it is believed to represent the Golgi apparatus in this organism.
The Supposed Pancreatic Organs of Petromyzon fluviatilis and Myxine glutinosa
Authors: Barrington E. J. W.
Published: April 2021

A new description is given of certain structures in Petromyzon and Myxine which, in view of their anatomical relationships and developmental history, have been considered by some earlier workers to be comparable with the pancreas of higher vertebrates.

They are composed of cords of cells which develop, at least in part, from the bile duct. In Petromyzon some of them are shown to be closely associated with a small caecum of the intestine.

They are not externally secreting structures, and in particular they do not in either animal communicate with the intestinal lumen, but there is histological evidence, more convincing in Petromyzon than in Myxine, that they may be endocrine organs.

In both animals secretory cells are present in the intestinal epithelium, and may be considered to represent the zymogen cells of the pancreas. Interpretation of the cords as islet tissue, however, cannot be established on histological grounds alone. Using the Helly-Azan technique, which successfully differentiates the cellular components of the latter in fish, it is shown that only one type of cell is present in the cords ; this does not give the characteristic staining reaction of A cells, and differs in certain respects from the B cells.

The significance of these results is briefly discussed in the light of the evolutionary status of the Cyclostomata.
On the Eyes and Reactions to Light of Proteus anguinus
Authors: Hawes R. S.
Published: April 2021

The structure of the eye has been reinvestigated. Development is arrested at the secondary optic vesicle stage, though growth continues for some time afterwards. The lens does not complete its differentiation; it usually disappears in adult animals, and is replaced by a proliferation of epithelial cells from the iris margin. If the lens persists this proliferation is inhibited. These facts are explicable on the assumption that the normal potencies of the iris margin are realized when the inhibitory action of the lens is removed, but, in Proteus, the typical dominance of the dorsal region of the margin is lost, so that the organization of the proliferated cells into a morphogenetic field does not take place.

The visual cells of the retina stop their development at about the time when rod and cone primordia first become distinguishable.

The optic nerve, greatly reduced, persists throughout life.

The vascular supply to the choroid is maintained through a minute vessel representing the ophthalmic artery.

The relations of the nerve and artery to the trabecula cranii are those of a typical urodele embryo and, in this respect, development in Proteus is arrested at a slightly earlier stage chan in Necturus.

The development of the extrinsic eye muscles is arrested before their adult arrangement is achieved and before the M. rectus internus appears.

The skin above the eye is unmodified and the accessory cornea of Schlampp does not exist.

It is argued that the condition of the eye and some other structures in the orbit is just as much the effect of neoteny as such typically embryonic features as the skin and gills. The general tendency to neoteny was present when Proteus first adopted a cavernicolous life and was able to extend to the organs of vision when their function became unnecessary.

Proteus is sensitive to stimulation by light and responds to it by movement. The eyes are unnecessary for light perception.

Stimulation of the body and tail at any intensity and of the head at low intensities produces slight movements of adjustment and, if repeated, may lead to movements of translation.

Stimulation of the head at high intensities leads to a violent and sudden turning response after a latent period of reaction, dependent, within limits, on the intensity of stimulation.

The active factor of the stimulus is intensity, not direction.

The reactions at high and low intensities and the types of orientations they produce (‘photophobotaxis’ and apparent ‘photokinesis’) are possibly not fundamentally distinct. The subjective impression of movement at random below the threshold for shock reactions is erroneous ; the movements are controlled, but the basis of control has not been discovered.

The light responses are not adaptations developed in relation to life in caves, in which they are never used. They are survivals from a period of epigean existence, and may have played a part in the colonization of caves by Proteus.
The study of Nephridia and Genital Ducts since 1895
Authors: Goodrich Edwin S.
Published: April 2021

From the analysis given above of recent work on the development of the nephridia in the Oligochaeta, it may safely be concluded: that it is now definitely established that the whole nephridium from funnel to pore (including the whole nephridiostome, the excretory canal, the bladder and duct to the exterior, but excepting an insignificant ingrowth of epidermis at the pore in higher forms), arises from a special cell, the nephridioblast; that the nephridioblast does not belong to the coelomic epithelium, is not derived from the coelomesoblastic band, but is of retroperitoneal origin, primitively occupies an intersegmental position, and only breaks through the coelomic epithelium at the point where the nephridiostome comes to open (Text-fig. 79).

Further, it is exceedingly probable, though not so definitely proved, that such nephridioblasts are derived in the higher Oligochaeta (Megadrili) from nephric bands or rows of cells formed by the repeated forward division of posterior nephric teloblasts situated at first in the surface layer of ectoblast ; or, if not from regular bands, at all events from originally superficial cells of ectodermal or ectomesodermal nature.

Usually, and possibly always, the nephridial canal develops as a string of cells, produced by the repeated backward division of the nephridioblast, which string becomes hollowed out by an intracellular lumen. The nephridiostome is formed by the division of the residual nephridioblast itself, though some of the must anterior cells of the string may contribute to it.

In this connexion it must be remembered that, like the larval protonephridia of the Polychaeta, the larval nephridia of the first segment in Oligochaeta appear certainly not to be developed from the coelomesoblast, but from ectoblastic or ectomesoblastic cells (cells 2c in Bimastus, according to Svetlov (1928)). They appear very early and in Tubifex even before the coelomesodermal teloblast has begun to divide (Ivanow, 1928). It may be concluded that, as long ago maintained by Vejdovsky, neither the embryonic nor the later nephridia are derived from the coelomesoblast.
The Study of Nephridia and Genital Ducts since 1895
Authors: Goodrich Edwin S.
Published: April 2021

In 1895 a general review of the morphology of nephridia and genital ducts, and their relation to each other and to the coelom, was published by me (Goodrich, 1895). The present paper is a similar review of the work done since that date on these organs throughout the Metazoa Triploblastica. It is shown that a great many newly discovered facts support the conclusions put forward in 1895, notably the conclusion that two different organs of independent origin—genital ducts and excretory nephridia— can be traced through the various Phyla of Triploblastica. The Gonocoel theory is accepted as the best explanation of the origin of the coelom. In all the various groups coelomoducts, primitively acting as genital ducts, are shown to be derived from the epithelial wall of the gonadial sac, or its derivative the coelomic sac, as centrifugal outgrowths which meet the ectoderm and come to open to the exterior ; whereas the excretory nephridia are to be derived from superficial rudiments, often in the form of nephridioblasts, which develop centripetally, and give rise to the whole nephridium whether protonephridial or metanephridial. The nephridial rudiments are not developed from the coelomesoblast, but are either of ectodermal or of ecto-mesodermal origin. The coelomoducts are always of coelomesoblastic origin. In some Polychaeta (and possibly some Archiannelida) nephridium and coelomoduct may combine to form a nephromixium of both excretory and genital function. In many groups some of the coelomoducts may secondarily acquire an excretory function. In such groups nephridia may disappear, or be no longer developed; provisional larval nephridia may, however, persist until the excretory coelomoducts are developed.

Suggestions for the improvement of the nomenclature of these organs and their specialized modifications are made (pp. 117,119). Incidentally many new unpublished observations on their structure and development are recorded. More particularly may be mentioned the early development and morphological relations of the nephridioblast in Tubifex (p. 271).
The Anatomical Memoirs of John Goodsir, F.R.S.
Authors: Turner W.
Published: April 2021

The name of John Goodsir is not, perhaps, so familiar to microscopical observers as that of many others who have done less service to science by the aid of the microscope. The fact is, the late Professor in Anatomy-prosecuted his researches in anatomy and physiology from a very exalted point of view, and the microscope was only used by him, as it always ought to be used, as a means of observation subservient to the higher-generalizations of biological science. At the same time these memoirs abundantly show that the microscope was one of the most frequent instruments employed in his anatomical and physiological researches. One of the earliest memoirs in these volumes is that on “The Development of the Pulps and Sacs of the Human Teeth; “and although not an exclusively microscopical subject, he could not have carried on his researches on this subject or have arrived at his conclusions without the aid of the microscope.
On Draparnaldia Crdciata, Hicks
Authors: Braxton Hicks J.
Published: April 2021

The Draparnaldia, of which a drawing for the first time is now given, was described by me in the ‘Journal of the Linnæan Society,’ November 18th, 1857. It was discovered by me in the gentle streams issuing from the bogs of the New Forest in several localities. Subsequently, among some drawings sent to me by Mr. G. S. Brady, Secretary of the Tyneside Naturalist Field Club, in order to be named, I was pleased to find a very accurate representation of this alga. It was found by him in the peat bogs near Crag Lough, Northumberland, and is mentioned by him, along with others found in the same locality, in the sixth volume of the ‘Trans. Tyneside Naturalist Field Club.’
Spermatophore Production in Rhodnius prolixus
Authors: Davey K. G.
Published: April 2021

On the basis of experimental and histochemical evidence it has been shown that the main body of the spermatophore of Rhodnius is a mucoprotein or neutral mucopolysaccharide originating in the transparent accessory glands of the male. A study of the events during copulation demonstrated that the spermatophore is formed inside the spermatophore sac, the folded terminal portion of the intromittent organ. Normally folded inside the base of the penis, the spermatophore sac is everted by the influx of the transparent secretion and acts as a mould for the spermatophore. The solidification of the fluid, transparent secretion inside the sac is the result of a lowering in pH brought about by the secretion of the bulbus ejaculatorius.
A Histochemical Investigation of the Pituitary Glands of some Teleost Fish
Authors: Matty A. J. , Matty J. M.
Published: April 2021

Some histochemical observations on the pituitaries of three marine and three freshwater teleost fish have been made. It has been shown that cells of this gland, which are stained identically in different species by Azan, do not always give identical histochemical reactions, and that in the same species cells which after histological staining have similar tinctorial affinities may be differentiated histochemically. These observations are discussed with regard to the function of the gland.
The Action of Fixatives on the Unmasking of Lipid
Authors: Clayton Blanche-P.
Published: April 2021

The capacity of various primary (unmixed) fixatives to split lipids from lipoprotein complexes was investigated. The lipoproteins that formed the test-objects of the research were those contained in (a) the acroblast of the cricket (Acheta domesticus), and (b) the endoplasmic reticulum (‘ergastoplasm’) of the acinar cell of the pancreas of the laboratory mouse. The two test-objects gave essentially the same results. Of the 16 compounds tried, cadmium chloride is the most powerful unmasker of lipids. Mercuric chloride is also a powerful unmasker, and gives much better fixation. Chloroplatinic acid and formaldehyde are moderately powerful unmaskers.
The Nature of a Chromosomal Phospholipid
Authors: Chayen J. , Gahan P. B. , Cour L. F. LA
Published: April 2021

It has been found that the heterochromatic region of interphase nuclei of plant roots and calf thymus, fixed in formaldehyde solution, do not stain for phospholipid as they do after Lewitsky’s fixative. It has been shown that this is probably due to the extraction of a protein-phospholipid complex. Some lipid-like material has been purified from the used formalin and shown to contain glycerophosphate. The nature of the association between the lipid and protein is discussed.
The Histology of the Nervous System of an Insect Rhodnius prolixus(Hemiptera): II The Central Ganglia
Authors: Wigglesworth V. B.
Published: April 2021

The central nervous system of Rhodnius has been studied in sections stained with osmium / ethyl gallate. The single type of glial cell responsible for perineurium and axon sheaths in the peripheral nerves becomes differentiated in the thoracic ganglia into four types.

Type i cells form the layer of perineurium cells filled with filamentous mitochondria. These cells which are rich in succinoxidase control the passage of all substances to and from the ganglion.

Type ii cells produce the thick myelin-type sheaths for the lateral group of motor axons (see below).

Type iii cells, the giant glial cells in the ganglionic layer, have a very extensive cytoplasm which sends deep tongue-like invaginations into the large ganglion cells. This cytoplasm must control the transmission of nutrients and excretory substances to and from the neurones. It contains some non-specific esterase.

Type iv cells form an investment of the neuropile. They also have extensive cytoplasm which surrounds the axons and dendrites and provides intensely staining inter-neuronal material in the synaptic regions. This material, the ‘darkly staining neuropile’, is the chief site of acetylcholine esterase.

The nerve-tracts are well displayed by the osmium / ethyl gallate method. The axons appear as unstained cords containing mitochondria, against the dark neuropile. The large motor axons of the legs separate into two groups. The medial group run directly into the neuropile and have thin sheaths. The lateral group remain outside the neuropile; they become narrow and enclosed in a thick myelin-type sheath; but as they turn into the neuropile the sheath becomes thin and the axons enlarge again.
The Histology and Activities of the Tube-feet of Echinocyamus pusillus
Authors: Nichols David
Published: April 2021

The histology of the suckered, buccal sensory, and respiratory tube-feet and their ampullae, where they occur, of the clypeasteroid sea-urchin Echinocyamus pusillus is described. Each suckered tube-foot possesses two sets of special muscles for attachment and detachment, a ring of mucous glands to assist in attachment, and a ring of sensory cilia. The stem retractors are in four columns, whose differential contraction provides the means of postural movement relative to the test. The ampullae of these tube-feet are exceedingly thin-walled, apparently musculo-epithelial, with anastomosing contractile elements. The canal between tube-foot and ampulla contains a swollen coelomic epithelium which may help to maintain the nerve relationships of the system. The activity of the suckered tube-feet is compared with that of the tubefeet of the starfish, Asterias rubens. The buccal tube-feet, larger than the suckered tube-feet, have large disks underlain by a thick nerve plexus supported by transverse fibres ; a ring of sensory cilia surrounds the disk. They have no mucous glands and no suckers, and are presumably entirely sensory, probably both tactile (the cilia) and chemoreceptive (the disk). The respiratory tube-feet are thin-walled sacs, the walls consisting of an outer ciliated and an inner non-ciliated (coelomic) epithelium with cross-connexions for support; where the coelomic epithelium lines the pair of canals through the test it is heavily ciliated. In the specializations of its tube-feet this urchin is shown to share some features with the regular urchins and others with the spatan-goids.
Spicule Growth Rates in Leucosolenia variabilis
Authors: Clifford Jones W.
Published: April 2021

The growth rates of spicules of Leucosolenia variabilis have been determined by photographing stretched pieces of the wall for a maximum period of 17 h. For 3 pieces, A, B, and C, the average rates for spicule rays above 25 μ in length were respectively 2 · 50 (18 – 21° C), 1 · 64 (18° C), and 1 · 29 (17 ° C) μ per h. The discrepancies are greater than would be expected from the differences in temperature.

For both basal and oscular rays the growth rate increases to a steady level as the rays lengthen. The basal rays grow precociously at first, but in A the oscular rays soon caught up with the associated basal ray, while in B and C (both derived from the same oscular tube) the oscular rays of the growing spicules tended to remain smallerthan the associated basal ray during the recorded period of growth. Whether this difference between the pieces was due to genetic factors or to the experimental conditions was not determined.

Above 25 μ in length the oscular and basal rays grow at similar rates, regardless of whether the rays belong to Y-, T-, or even aberrant spicules. The orientation of the optic axis of the mineral constituent has thus no appreciable effect on the growth rate.
The Mesogloea of Pelagia noctiluca
Authors: Chapman G.
Published: April 2021

The arrangement of the mesogloea fibres of Pelagia noctiluca is described chiefly from material examined in the fresh state.

The role of the mesogloea in swimming is shown to be the antagonization of the subumbrellar circumferential muscles.

The fibres of the mesogloea are shown to be collagenous by their contraction on heating, their amino-acid composition, and their appearance under the electron microscope.

A suggestion is made to account for the characteristic arrangement of the fibres at a distance from the cellular layers.
An Occurrence of Hermaphroditism in Rana catesbiana
Authors: O’steen W. Keith
Published: April 2021

Hermaphroditism is rather uncommon in the bullfrog, Rana catesbiana. A case is described here. Among the features of the unusual urogenital system were male secondary sexual characters (large tympanic membrane, vocal sacs, nuptial pads), testicular tissue with developing and mature male gametes, and accessory ducts (vasa efferentia, seminal vesicles). Müllerian ducts and large ovarian masses containing oöcytes and mature ova were also present. Oocytes were observed in the lumina of seminiferous tubules.
A Modification of the ‘Hermann PO’ Method for Mitochondria
Authors: Jordan-Luke Barbara M.
Published: April 2021

Hermann’s fluid is an excellent fixative for mitochondria, provided that the tissue is postosmicated; and if the postosmication is carried out for several days at 34° C, the mitochondria are blackened (Baker, 1957). This is probably the easiest and most satisfactory way of making mitochondrial preparations for light microscopy. Filamentous mitochondria retain their form.
The Nissl-Golgi Complex in the Purkinje Cells of the Tawny Owl, Strix aluco
Authors: Malhotra S. K.
Published: April 2021

The purpose of this investigation was to repeat as exactly as possible the original work on the ‘apparatus’ of Golgi in the Purkinje cells of the cerebellum of owls, and to re-investigate these cells by modem methods. The tawny owl, Strix aluco, was used instead of the closely-related ‘Strix flammea’ of Golgi. Golgi’s ‘osmio-bichromique’ technique of 1898 for silver impregnation was used successfully.

A reticulum corresponding to the basiphil Nets of Nissl can be seen in the living neurones by interference microscopy. The classical Golgi apparatus of the perikaryon is a deposit of silver or of osmium on this reticulum. The reticulum extends into the axons in the form of thin non-basiphil filaments, which are also blackened by Golgi methods.

These findings are in conformity with recent studies of the neurones of other vertebrates.
A Method of Silvering the ‘Golgi Apparatus’ (Nissl Network) in Paraffin Sections of the Central Nervous System of Vertebrates
Authors: David G. B. , Mallion K. B. , Brown A. W.
Published: April 2021

I. It was accidentally found that methods of silvering synaptic end-feet sometimes blackened Golgi’s ‘internal reticular apparatus’ in neurones of the central nervous system of the cat.

2. A method of achieving this consistently was worked out: (a) paraffin sections are coated with a collodion membrane; (b) the collodion membrane is soaked in silver nitrate; (c) the silver nitrate is reduced to metallic silver with a buffered formaldehyde solution; (d) steps (b) and (c) are repeated until the sections appear quite black; (e) the silver attached to structures other than the Golgi apparatus is removed with a ferricyanide/thiosulphate bleach; (f) the section is ‘toned’ with gold chloride, fixed in thiosulphate, and washed thoroughly; (g) the section is dehydrated, cleared, and finally mounted in Canada balsam, DPX, or similar media. Results: Golgi-apparatus, black; connective-tissue fibres, black; axons, grey to black; everything else is light grey or colourless.

3. A tentative hypothesis is advanced to explain the results obtained.

4. The following advantages are claimed for the new method: the cytoplasmic reticulum thus blackened resembles that seen in living neurones with the interference microscope; special methods of fixation are not required; the cytoplasmic reticulum of given cells can be studied before and after silvering; and serial sections of the same piece of tissue can be used for histochemical purposes.