bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ‘Segmentation Cavity’ of the Egg of the Frog.
Authors: Meek Alexander 
Published: April 2021

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACTIn 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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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.