bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Cytoplasmic Inclusions of the Germ-Cells. PART III. The Spermatogenesis Of Some Other Pulmonates.1
Authors: Gatenby J. Brouté 
Published: April 2021

ABSTRACT
Eight species of Pulmonates have been carefully studied, and certain stages of four more species examined. A new set of plasmatic bodies, the post-nuclear granules have been described. The P.N. granules differ from the mitochondria in their staining affinities, but resemble them in size. The P.N. granules ultimately form a plate at the rear of the spermatid nucleus. This plate, at first large, gradually shrinks synchronously with the shrinkage stages in the nucleus. The P.N. granules appeal’ to become non-staining during the maturation division, but it is not known whether more intense chromatization of the material (Benda) might not bring them into evidence. The mitochondria of the Pulmonates so far studied are of the same general type. On p. 239 twelve conclusions are given with regard to the mitochondria both of Pulmonates and of other forms. The chondrioplasts of all the Pulmonates dealt with have been fully examined. The chondrioplasts of different genera and often of different species tend to differ a little in shape aud size. The chondrioplasts during the prophases of the first maturation karyokinesis lose a great deal of their staining affinity. In many cases during the metaphase, anaphase, and telophase it cannot be demonstrated without specially heavy chromatization and staining. During these periods it changes, in its chemical constitution. The centrosome is responsible for the sorting out of the chondrioplasts into two equal groups at the prophase of division. The batonette is not divided by fission, but goes to the daughter-cell complete. After the final maturation division is over, the chondrioplast rod resumes its lost staining affinity. The chondrioplast batonettes do not take direct part in the formation of the spindle. The micromitochondria have been thoroughly re-examined with iron hæmatoxylin and Benda’s method. Their presence is confirmed by all tests that could be made. They seem to differ in staining capacity from the macromitochondria. The presence of micromitochondria in other forms is doubtful, because the cells are so small as to make proper examination impossible. Micromitochondria appear to be present in Limax agrestis and in H. rufescens. The mitochondria, during the maturation divisions, stain less heavily, and often become larger. The latter fact could not be demonstrated in every case. On p. 248 I have stated the periods during which the mitochondria, appear to alter in staining affinity and resistance to certain fixatives. The affinities of the several species have been discussed on the basis of their cytoplasmic bodies. Tables of staining and fixing effects have been given. From the three papers already published on the “Cytoplasmic Inclusions “it will be seen that strong evidence is being collected against the view that the mitochondria take any part in the transmission of the “factors of heredity.”
Ecdysis in a Teleostean Fish, Agriopus
Authors: Gilchrist J. D. F. 
Published: April 2021

ABSTRACT
Agriopus is a well-known fish of the Southern Hemisphere, and is recorded from South America, South Africa and Australia. On account of its striking appearance it attracted the attention of early travellers, and is first mentioned by Block under the name of Coryphæna torva. It has a mane-like dorsal fin and a long vertical forehead, from which it derives its local name “Horse-fish.” A further characteristic, mentioned by all observers, is its soft, thick skin devoid of scales. This was specially noted by Cuvier and Valenciennes, who describe the skin of A. tor vus as “épaisse et lisse comme un cuir’ bien préparé, sans aucune apparence d’écailles.” They add that, among the specimens procured, there were some in w’hich the skin was quite brown and raised in small wart-like prominences, so well marked as to suggest that these individuals represented a different species, though otherwise not dissimilar.
On the Blood-Vase alar System of the Earthworm Pheretima, and the Course of the Circulation in Earthworms
Authors: Narayan Bahl Karm 
Published: April 2021

ABSTRACT
The typical arrangement of the blood-system in Phere-tima occurs in the region of the body behind the fourteenth segment, the first fourteen segments forming the cephalized region. The main longitudinal trunks are the same as in Lumbricus, except that the lateral neurals are absent as in Allolobophora. The dorsal vessel receives two pairs of dorso-intestinals and one pair of commissurals in each segment behind the cephalized region. The intestinal blood-plexus is both an external and an internal one, and three regions can easily be distinguished. The first is internal, and extends from the fourteenth to the twenty-sixth segment ; the second is both external and internal, is co existent with the typhlosole, and extends over the larger part of the gut ; and the third is only external, and is confined to the rectal or post-typhlosolar part of the gut (last twenty-three to twenty-six segments). The commissural vessel of Pheretima is a compound vessel, and represents both the ‘dorso-sous-nervien ’ of Lumbricus and theintestino-tegumentary of Megascolex. The capillaries of the integument are not like these of Lum-bricus but like these of Moniligaster, and there is a close ’parallelism ’ between an ‘artery ’and a ‘ vein ’in the body-wall, in which the two pass into each other through a number of capillary loops. There are four pairs of ‘hearts’ which connect the dorsal with the ventral vessel, and five pairs which supply blood directly to the various organs in the cephalized region. There are two pairs of non-contractile ‘anterior loops’ connecting the lateral oesophageals with the supra-intestinals, these loops being the counterpart of the connexions of the lateral oesophageals with the dorsal and the parietal in the tenth and twelfth segments respectively of Lumbricus. The subneural vessel is absent in the first fourteen segments, and is continuous with the lateral oesophageals of the anterior region. As regards the course of circulation of the blood, the chief fact is that the dorsal vessel is wholly ‘venous’ behind the ‘hearts’ and wholly ‘arterial ’ in the region of the ‘hearts ’ and in front (the whole of the cephalized region). The examination of valves and experiments by cutting and pinching the blood-vessels in Pheretima confirm the results of Johnstone for Lumbricus as regards the course of blood in dorso-intestinals and commissurals and make Bourne’s theory untenable. The ventral vessel is the arterial trunk throughout, while the venous function of the dorsal and subneural behind is taken up by the lateral oesophageals in the cephalized region. The thin-walled and non-contractile ‘loops’ of the tenth and eleventh segments must be distinguished from the thick walled and contractile ‘hearts’ of the other cephalized segments, the ‘loops ’ being the channels for conveying blood from the lateral oesophageals to the supra-intestinals.
Studies in Dedifferentiation.: II. Dedifferentiation and resorption in Perophora
Authors: Huxley Julian S. 
Published: April 2021

ABSTRACT
The social Ascidian Perophora viridis may dedifferentiate in either of two distinct ways, or by a mixed method: (a) by reduction to a spheroidal mass, as in Clavellina; (b) by incipient reduction as in (a), but followed by total resorption into the stolon, which may grow during the process. Resorption is due to the migration of the individual cells out of the tissues into the haemocoel. In certain conditions the zooid maintains itself, in spite of food not being provided, at its original size and in perfect health. This it does by resorbing the stolon. Experiments with dilute solutions of KCN show that resorption of the zooid occurs in slightly unfavourable conditions, which affect the sensitive zooid, more than the less highlyorganized stolon. The results are to be explained as follows: (a) In the competition between zooid and stolon the zooid normally is dominant because metabolic processes take place at a greater rate in it than in the stolon. The stolon is therefore starved at the expense of the zooid, (b) The zooid is more susceptible than the stolon to toxic agencies, (c) In low concentrations of such agencies it is therefore affected while the stolon is not. (d) As a result it begins to dedifferentiate. Dedifferentiation is here accompanied by the migration of the cells out of the tissues, (e) The speed of its metabolic processes is now no longer greater than that of the stolon’s. It is therefore now starved at the expense of the stolon, (f) Any cells migrating out of the tissues are removed by the normal circulation, by the stoloncirculation (irregular pulsation of the stolon), or by utilization as food by the stolon. As in chemical reactions where the end-products are removed, the reaction thus runs to its limit, i. e. to complete resorption of the zooid. Stopping the circulation by means of KC1 results in dedifferentiation accompanied by a much smaller degree of resorption. At low temperatures (about 5° C.) some dedifferentiation occurs; but there is very little resorption, apparently owing to the cessation or slowing of the heart-beat. Partial dedifferentiation is recorded in Amaroucium and Botryllus. The significance for general biological problems of dominance due to high rate of metabolism, of differential susceptibility and of dedifferentiation, is discussed. The similarity of certain psychological and neurological phenomena is noted (mental regression, alteration of spinal reflexes when freed from cerebral control, &c.).
Surface Tension and Cell-Division
Authors: Gray J. 
Published: April 2021

ABSTRACT
The series of changes which a dividing cell exhibits has long suggested to biologists that surface tension plays a dominating rôle in the process of cleavage. Without exception, theories based on this suggestion have postulated regions of differential tension on the cell-surface ; the surface tension at the equator of the cell has been held to be either higher or lower than that at the polar regions of the cell. Such theories have proved of but little value as a means of further investigation, since there is no apparent means of determining how such a state of affairs could arise, nor is there any apparent differentiation in the microscopical structure near the equator of the cellsurface.
The Formation of the Peritrophic Membrane in Insects, with Special Reference to the Larvae of Mosquitoes
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
In the larvae of mosquitoes (Anopheles, Culex, and Aedes) the secretion from the cells of the cardia, in the proventriculus, is drawn through an annular press and thereby moulded to form the peritrophic membrane. The mechanism of this press has been described in detail.
It seems probable that, throughout the Diptera, the peritrophic membrane is formed by similar mechanisms. Figures are given of those in the larvae of S ciar a (Cecedomyidae), Rhyphus (Rhyphidae), and Telmatoscopus (Psycho-didae).
Analogous structures (a zone of secreting cells in connexion with an annular press) have been found in most of the main orders of insects, as follows : Hymenoptera [adult of Bombus and Apis and the larva of a saw-fly (Tenthredinidae)] ; Coleóptera [larva of the mealworm (Tenebrio molitor) and the adult of Coccinella]; Lepidoptera [larvae of Cheima - bacche fagella (Oecophoridae), Sitotroga cerealella (Gelechiadae) and Ephestia kuhniella (Pyralidae)] ; Aphaniptera (larva of Ceratophyllus wickhami); Iso-ptera ; Neuroptera (adult of Hemerobius); Odonata (larva of Aeschna); Orthoptera (Blatella germánica); and Dermaptera.
In every case, in addition to its function as a press, the so-called ‘oesophageal valve’ was found to act not as a valve but as a sphincter.
In the honey-bee (Apis), the larva of the dragon-fly (Aeschna), and possibly in other insects, indefinite membranes are shed off by the cells farther back in the mid-gut, and added to those produced in the annular press.
In all the insects examined, chitin formed the basis of the peritrophic membrane.
The observations recorded give a coherent significance to much of the previous work on the subject, which, before, appeared contradictory.
On the behaviour and structure of cells of Helix aspersa in aseptic and non-aseptic tissue culture
Authors: Gatenby J. Brontë , Hill Joyce O. , Macdougald T. J. 
Published: April 2021

ABSTRACT
In a previous paper in this Journal (16), the two senior authors have given some account of the behaviour of small pieces of the wall of the mantle cavity of Helix aspersa, kept in Hédon-Fleig saline. Since our last communication a considerable amount of work has been done by two of us. (J. C. H. and T. J. M.) on this cultivation in vitro, the main object of which has been to obtain aseptic growths. A more intensive study of various media has been made, and we have found it comparatively easy to obtain aseptic cultures, even in a room which could not be used expressly for this type of work.
The Life-History of Sacculina
Authors: Day J. H. 
Published: April 2021

ABSTRACT
This paper contains a revised version of the life-history of Sacculina stressing certain points which have arisen as a result of work on the effects of the parasite on its host.
From the statistical analysis of a year’s samples of an infected crab population it is concluded; first, that crabs may be infected at any age; secondly, that the developmental sequences in the life-history of the parasite are dependent not on the season but possibly on the phases of the host; thirdly, that the internal development of the parasite lasts nine months, and that the first batches of larvae appear three months later.
Two separate experiments showed that the évagination of the parasite does not take place at an ecdysis of its host.
It is suggested that an anomalous group of highly modified male crabs without externae but containing living parasitic roots are ‘scarred crabs’ that have moulted; further, that such modified crabs will in time regenerate externae. Experimental and histological evidence supports this suggestion, but it is not held that the theory of regeneration is completely proved.
An account is given of the effects of Sacculina on the secondary sexual characters of Portunus holsatus. Only male crabs are dealt with. It is shown: (a) that various degrees of modification are possible; (i&gt;) that the percentage of infection increases among large crabs; (c) that the smaller the crab the greater the liability to maximum modification; (d) that the maximum amount of modification which is possible decreases among larger crabs.
On the Post-embryonic Development of the Respiratory System of Dialeurodes dissimilis (Homoptera, Aleurodidae)
Authors: Roonwal M. L. 
Published: April 2021

ABSTRACT
Accounts of the post-embryonic development of the tracheal system of any insect are extremely meagre. The development of the breathing-folds has not been studied in any of the Aleurodidae. The present account is concerned with the post-embryonic development of the respiratory system (the tracheal system and the breathing-folds) in the nymphs of Dialeurodes dissimilis Quaintance and Baker (Aleurodidae, Homoptera). The number of spiracles in all the nymphal instars is four (probably five in the first instar). They lie on the ventral surface of the nymphs but their exact position varies in the different instars. The third pair of spiracles is replaced by an entirely new one in the third instar. The spiracles, as studied in the pupa, are of a simple type and have no closing mechanism. The tracheal system consists fundamentally of paired ventral- and dorsal-longitudinal tracheal trunks, two dorsalcommissural tracheae, the spiracular and palisade tracheae, and the various branches of the main system. Growth of the tracheal system consists, on the whole, of arborescent branching from the main system, but there also occur some interesting changes of atrophy. All these changes are described in detail. The final number of tracheal branches (in the pupa) is constant, and is 156. There is a gradual shifting backwards of the tracheal system with reference to the body segments. Some of the tracheal branches which in the pupa are apparently homologous actually develop heterochronously. The structure and development of the breathing-folds is described and their function discussed.
The Cytoplasmic Inclusions in the Spermatogenesis of Man
Authors: Gatenby J. Bronte , Beams H. W. 
Published: April 2021

ABSTRACT
The points which we have brought out in this paper are:The development of the acrosome from the Golgi apparatus, which has been figured for the first time during growth, and the stages of acrosome formation in the human.The almost complete break-up of the Golgi apparatus at dictyokinesis, and the late reassembly of the fragments apparently independently of the spermatid centrioles.The very probable presence of a neck granule apparatus as distinct from the head or proximal centriole (c1).The claim that the head centriole does not divide. The emergence of the flagellum from the proximal and distal centrioles jointly.The development of the post-nuclear cap in human spermatids.The apparent absence of any form of spiral body in the middle-piece.The different types of Golgi apparatus in the Sertoli and spermatogenic cells.The presence of a vacuole in the head of the spermatozoon.The remarkable ‘nutrient syncytium’ connected with the Sertoli cells.The accessory body in the cytoplasm.
The Development of the Adrenal Gland of the Mouse
Authors: Waring H. 
Published: April 2021

ABSTRACT
The cortical anlage is constituted from the mesenchyme at about the 12th day of embryonic life. The medullary anlage is constituted at about the 13th day of embryonic life from the anlage of the sympathetic nervous system and lies closely adpressed to the cortical anlage. At about the 14th day sympatho-chromaffin elements migrate from the closely adpressed sympathetic nervous mass into the cortical anlage and form irregularly arranged ‘nests’ in its substance. Between 16 and 18 days of foetal life part of the cortical substance has differentiated by becoming less eosinophil and is destined to form the adult permanent cortex. By the day of birth the sympatho-chromaffin elements are concentrated at the centre of the gland and are beginning to metamorphose into medullary cells.
The undifferentiated eosinophil cortical tissue now forms a layer immediately outside the medulla and interlocking with the medullary tissue.
The less eosinophil tissue now shows the first distinct signs of the arrangement characteristic of the adult glomerular and fasciculate zones. After birth, in both sexes, the interlocking zone increases, attaining its maximum at about 21 days in the male but continuing to increase in the female, so that at about 25 days there is a distinct sex difference.
The three zones of the adult cortex are distinguishable in both sexes by 25 days—the glomerulosa, zona fasciculata, and zona reticularis.
The reticular zone is distinctly a product of the zona fasciculata and not of the interlocking eosinophil zone. At 30 days in the male degeneration of the interlocking zone has begun—in the female the zone is still increasing. The male reticular zone is now very clearly developed but that of the female has remained at the 25-days condition.At 35 days in the male degeneration of the interlocking zone has become well established. In the female this zone attains its maximum development at about this period.By 56 days in the male the degeneration of the interlocking zone is complete, leaving a connective tissue capsule between the medulla and the well-marked zona reticularis of the permanent cortex. (The female is not discussed beyond 35 days.)The interlocking zone of the adrenal of the mouse (X-zone of Miller) is shown to be probably homologous with the boundary zone of man and of the cat.
The Germinal Layers concerned in the Formation of the Alimentary Canal and Malpighian Tubules of Epbestia Kühniella (Lepidoptera)
Authors: Drummond Mabel 
Published: April 2021

ABSTRACT
The mid-gut epithelium of Ephestia is derived from cephalic and caudal mesendoderm rudiments which are proliferated from the germ-band independently of the stomodaeal and proctodaeal invaginations. The oesophageal valve is formed by the backward growth from the blind end of the stomodaeum of six tubules, which later in a slightly altered form extend into the cavity of the mid-gut to form the valve of the larva. The stomodaeum and proctodaeum are purely ectodermal. The malpighian tubules are ectodermal.
Nobert’s Test-Plate and Modern Microscopes
Authors: Stodder Charles 
Published: April 2021

ABSTRACT
Every possessor of a first-class microscope wishes to know what his instrument is capable of doing. To the practical worker it is a matter of much importance, for when the utmost power of his instrument is exhausted he will know that it is a waste of time to endeavour to see more. One of the desirable and important properties of a microscope is the power to show or “resolve” very fine lines grouped together, e.g. the striation of the frustules* of the Diatomaceæ. For the purpose of testing the resolving power of the microscope, the lines ruled on glass by F. A. Nobert, of Barth, Pomerania, have long been admitted by experts as the best known test, not only in consequence of their exceeding fineness, but also because they are ruled to a known scale, and because they are so close that physicists have asserted that it is impossible that they ever can be seen, Nobert himself being in this category; and all trials of these plates, except those to be herein mentioned, have resulted in failures to resolve the finer lines of these plates.
Experiments on Young Salmon*
Authors: Mcintosh W. C. 
Published: April 2021

ABSTRACT
Early in 1862, and in the winter of 1862-3, the development of numerous salmon ova was observed, and some experiments performed on the young fish. Unfortunately, these had to be laid aside in March, 1863, for more pressing engagements, with the intention of again resuming them on a favorable opportunity; but since this has not occurred, the results—such as they are—are now briefly narrated. I may likewise state that during the progress of the experiments much valuable advice was kindly given by Prof. Christison, some of whose experienced suggestions were not fully carried out, on account of the sudden interruption of the work.
The Spermatheca of Loligo vulgaris: I. Structure of the Spermatheca and function of its Unicellular Glands
Authors: Oordt G. J. van 
Published: April 2021

ABSTRACT
The structure of the spermatheca of Loligo vulgaris is described; it lies on the inner wall of the buccal membrane and within it large quantities of inactive spermatozoa are stored.
This inactivity of the spermatozoa within the spermatheca is attributed to the effect of the secretion of the goblet-cells, situated as unicellular glands on the inner wall of the spermatheca.
Inactive spermatozoa from the spermatheca become very active in sea-water, but are immobilized again after a few moments’ contact with the pulp of the spermatheca contents.
The hydrogen-ion concentration of the spermatheca contents is approximately 6-06; and, since spermatozoa become inactive in sea-water, the hydrogen-ion concentration of which is increased to this level, it seems probable that the inactivity of the spermatozoa within the spermatheca is due to the presence of hydrogen-ions.
The spermatheca is functionally comparable to the mammalian epididymis.