bluuebunny/crossref_metadata_2025_split huggingface dataset:
The primordial germ cells of the chick I. the effect on the gonad of complete and partial removal of the ‘germinal crescent’ and of removal of other parts of the blastodisc
Authors: Goldsmith Joseph B. 
Published: February 2005

AbstractThe ‘germinal crescent’ of the primitive streak stage chick embryo is located in the zone of junction anterior and lateral to the proamnion. The primordial germ cells supposedly arise from this area.The following experiments were carried out. 1. Complete removal of the germinal crescent. 2. Partial removal of the germinal crescent. 3. Removal of areas of corresponding size of the blastodisc other than the germinal crescent.The results are as follows: In experiment 1, a careful search of the entire specimen failed to reveal any primordial germ cells. Such embryos invariably died during or before the fifth day of incubation.In experiments 2 and 3, the presence of the primordial germ cells was quite obvious. Such embryos did not invariably die. Some from each group was brought through to hatching, with the exception of that group in which the piece was taken from the lateral region of the blastodisc. In this case the injury to the circulation was too great to overcome.As was to be expected, in those specimens in which the circulatory system was injured rather severely death always ensued and occurred before the third day of incubation regardless of the type of experiment.Both cauterization and removal with scissors were tried. Mechanical removal gave superior results and was used exclusively in the latter part of the experiment.
The contractile vacuole of paramecium multimicronucleata
Authors: King Robert L. 
Published: February 2005

AbstractEach contractile vacuole system of Paramecium multimicronucleata is made up of a number of components, some temporary and others permanent. The contracting vacuole with its membrane is a temporary structure as are the vesicles which fuse to form it. The vacuole discharges its contents to the exterior leaving a vestige closing the pore. The pore, with its discharging tubule and the feeding canals are permanent cell organelles. The feeding canals end in injection tubules which extend up to the pore. The vesicles, which later fuse to form the vacuole, are formed at the proximal end of the injection canals, leaving a membrane closing the canal, much as a food vacuole is formed at the gullet. The canal‐fed contractile vacuole of Paramecium is very similar to the vesicle‐fed vacuole of Euplotes both as to its origin and its fate. The Nassonov homology is rejected.
The chromosomes of cryptobranchus allegheniensis
Authors: Makino Sajiro 
Published: February 2005

AbstractThe number and behavior of the chromosomes have been investigated in the spermatogenesis of Cryptobranchus allegheniensis. The spermatogonium contains sixty‐two chromosomes, which are composed of twelve atelomitic V‐shaped ones, and eighteen long and thirty‐two short telomitic ones. The haploid number of chromosomes is ascertained to be thirty‐one in both of the primary and secondary spermatocytes.The chromosomal relation between the present species and Megalobatrachus japonicus, a closely related form, has been discussed.
The intergeneric homology of an atypical euchromosome in several closely related Acridinae (order orthoptera)
Authors: Carlson J. Gordon 
Published: February 2005

AbstractAn atypical euchromosome, characterized by the large size and deep stainability of its chromomeres during the meiotic prophase, occurs in representatives of seven genera of Acridinae, viz., Chorthippus curtipennis, Euchorthippus pulvinatus, Stenobothrus lineatus, Omocestus ventralis, Stauroderus biguttulus, Gomphocerus rufus, and Aeropedellus clavatus. This element, which is termed the ‘megameric chromosome,’ stains more deeply than the other euchromosomes also during interkinesis and early spermiogenesis. The megameric chromosomes of the individual exhibit striking similarity in the number, size, and arrangement of their chromomeres through successive stages of the meiotic prophase. All the evidence from cytological study indicates that these chromosomes are intergenerically homologous. This is chiefly significant in the support it gives to the theory of chromosome individuality. The heteromorphic megameric tetrad of one individual of S. biguttulus—unequal because of a deficiency—usually undergoes segregation in the second division. The megameric chromosomes display splits previous to synapsis. Pairing begins at their proximal ends and proceeds distally. All the euchromosomes of the spermatid nucleus show splits in preparation for the first cleavage division of the zygote.
The origin of new epidermal cells in the skin of normal and x‐rayed frogs
Authors: Cameron John Andrew 
Published: February 2005

AbstractThe skins of normal and x‐rayed tadpoles and frogs were compared. Almost no mitotic figures occurred after the tenth day of larval life. The number of mitoses and the length of the period during which mitosis occurred were reduced by x‐rays in proportion to the exposure. Spindle‐shaped cells were found on the vertical connective tissue fiber bundles which connect the lower layer of the dermis with the under side of the epidermis in adult frogs. After exposure to 4000 r the number of these cells, which are believed to be traveling up the vertical strands to join the epidermis, was doubled. New, uninjured cells appeared in the basal epidermal layer following this increase. Since no appreciable number of mitotic divisions and no amitotic divisions were found in the epidermis, either normally or during the regeneration following exposure to x‐rays, these ‘traveling‐cells’ are held to be an important source of replacement in correlation with normal desquamation as well as desquamation caused by the irradiation.
The metamorphosis of Drosophila melanogaster, including an accurately timed account of the principal morphological changes
Authors: Robertson Charles William 
Published: February 2005

AbstractDuring the quiescent fourth larval instar the larva of Drosophila becomes loosened from the puparium and takes on the form of a pupa. A large gas bubble is formed within the body during this prepupal period. At the end of this stadium, which lasts 11 1/2 hours at 25°C., it pupates, shedding the prepupal cuticle. The gas bubble is used as a mechanism to separate the cuticie from its hypodermis. Practically all of the tissues undergo histolysis and are replaced by imaginal structures derived from specialized cells. Some of the muscles persist longer than the general mass and perform special functions in the pupa. The sequence of histolytic and histogenetic changes is accurately timed at a constant temperature.
The effect of fat extraction on Golgi bodies of kidney cells of the frog
Authors: Eastlick Herbert L. 
Published: February 2005

AbstractFrog kidney, when fixed in 4 per cent formalin and subsequently treated with Kolatchev solutions, is found to contain osmiophilic bodies which not only appear identical to the Golgi substance of Kolatchev fixed controls but which also resist bleaching in hydrogen peroxide or potassium permanganate solutions. If a formalin fixed kidney is dehydrated and extracted with various fat solvents and subsequently fixed with the Kolatchev technique, Golgi bodies are usually completely removed but occasionally cells are found which contain spherical globules of osmiophilic substance scattered through the cytoplasm.Kidney tissue fixed in a mixture of 95 parts of alcohol plus 5 parts of formalin before application of the Kolatchev solutions does not contain Golgi bodies. The same results are obtained if benzene is used instead of alcohol and formalin. Striated muscle, when treated in a similar manner, contains darkly stained (Z) and (M) membranes, therefore the osmophilic substance present in muscle quite widely daerent, chemically and physically from that contained in kidney cells.It is apparently an established fact that formalin preserves phospholipids in tissues nnd this investigation has shown that Golgi bodies in kidney cells can be demonstrated following fixation in formalin. Moreover, the Golgi bodies, which are preserved by formalin, can be removed by extracting the tissue with fat solvents. This evidence, therefore, strengthens the hypothesis that true Golgi substance is phospholipid in nature.
On the venous system of the common Indian rat‐snake ptyas mucosus (Linn.)
Authors: Ray Harish Chandra 
Published: February 2005

AbstractThe venous system of Ptyas mucosus (Linn.) presents the following features which appear to be hitherto undescribed in Ophidia: (1) Direct connection of the anterior azygos vein with the lateral cephalic vein just behind the head and also its anastomosis with either of the common jugular veins (right or left). (2) Anastomosis of the right and left common jugular veins with the epigastric vein in the neck region. (3) Left common jugular vein larger than the right. (4) Origin of the oviducal sinuses directly from the afferent renal veins and their termination on either side directly into the postcaval. (5) Persistence of the posterior cardinal veins in both the sexes. (6) Opening of most of the branches of the epigastric vein directly into the vena mesenterica in the liver region and of a few only into the right lobe of the liver. (7) Branches from the meso‐rectum contributing to the formation of the vena mesenterica. (8) Opening of some veins into a branch of the epigastric vein lying just behind the heart, which carry blood from the dorsal surface of the right lung, trachea, pericardial wall, and also from the parietal layer of the body wall on the left side.
The cytological changes in the hypophysis cerebri of the garter snake (Thamnophis radix) following thyroidectomy
Authors: Siler Kenneth A. 
Published: February 2005

AbstractChanges in the hypophysis cerebri of the garter snake, Thamnophis radix radix Baird and Gerard, were found in the anterior lobe of the nineteen thyroidectomized animals reported. Chromophobic cells enlarge and acquire a basophilic granulation, to become apparently normal beta (basophilic) cells. These, along with the beta cells originally present, become vacuolated, lose their granular content, apparently by liquefaction of the granules, and finally degenerate. The hypophyses of animals kept at 90°F. after thyroidectomy do not show degeneration of beta cells to the same degree that glands from animals kept at 70°F. (approximately) do. A reduction in the number of alpha (oxyphilic) cells is found under all conditions. A brief description of the morphology and normal histology of the gland is included.
The behavior of the karyosome and the ‘peripheral chromatin’ during mitosis and interkinesis in Amoeba proteus with particular reference to the morphologic distribution of nucleic acid as indicated by the Feulgen reaction
Authors: Chalkley H. W. 
Published: February 2005

AbstractA comparison of preparations stained with Weigert's haematoxylin and with Feulgen's stain shows that contrary to the commonly accepted view the granules of chromatin (sic.) that lie in interkinesis just beneath the nuclear membrane play no part in the formation of the chromatin of the equatorial plate, but break down during the prophase. They contain at best merely traces of nucleic acid. It is possible that these peripheral granules give rise to, or contribute to, the formation of the spindle fibers and the pole caps. The chromatin granules of the plate arise entirely from the karyosome.
Studies on the comparative histology of the digestive tube of certain teleost fishes. III. A bottom‐feeding fish, the sea robin (Prionotus carolinus)
Authors: Blake Irving H. 
Published: February 2005

AbstractThis paper presents the third of a series on comparative microscopic anatomy of the entodermal tract of certain teleost fishes, selected for their feeding habits: A study of the histology of the digestive tube of a bottom‐feeding species, the Carolina sea robin (Prionotus carolinus (L.)). Mainly from study of sections, but dissections of both fresh and preserved material were employed to furnish the necessary background of gross anatomy. A short résumé of the literature is given. Treats the general histology of the different divisions of the tube, the tunics and tissues present, and findings on structure and arrangement of cells. Particular emphasis is placed on histological adaptations to meet the demands of physiological processes. Escphagus, stomach, intestine and pyloric caeca are given detailed treatment. The tunica mucosa, with its histological constituents and their arrangement, receives particular stress, being considered in relation to various phases of digestion and absorption. Particular consideration is given to the following: Effects of amount of food present in the tube on extent of mucosal folding; histological transitions from one region of the tract to another, particularly as regards epithelia; histology of peptic glands in cardiac division of stomach; origin and development of mucosal goblet cells; comparisons between the histology of the pyloric caeca and that of the adjacent intestine from which they arise, together with a detailed account of the histology of the former.
The development and metamorphosis of the mid‐intestinal epithelium of Acanthoscelides obtectus (Say) (Coleoptera)
Authors: Bushnell Ralph Judson 
Published: February 2005

AbstractTwo sizes of cells are found in the mid‐gut epithelium of late embryos. The larger cells contain nuclei having twice the number of prochromosomes and nearly twice the volume as compared with the nuclei of the smaller cells. During each larval instar, the nuclei of the functional mid‐gut epithelium nearly double their volume and there is a corresponding increase in the amount of chromatin. It is suggested that chromosome division without nuclear division occurs in these epithelial cells during the pre‐ecdysial periods of each instar. The mid‐intestinal epithelial cells and their nuclei undergo characteristic changes during the feeding and pre‐ecdysial periods of each instar. Prochromosomes as well as cytoplasmic globules, which represent a cytoplasmic diminution process, are visible in the latter period. The regeneration cells which give rise to the pupal and mid‐gut epithelia have origin from the small embryonic mid‐gut cells and from nuclei and cytoplasm derived from the larval epithelium by means of an apparent ‘pseudoreduction’ of the large larval nuclei during the late third and fourth instars.
The anatomy of the male genital ducts in the fowl
Authors: Gray J. C. 
Published: February 2005

AbstractThe epididymis in the male bird consists of the rete testis, ductuli efferentia, and epididymal tubules. The rete testis is lined with cuboidal epithelium not resting on a basement membrane. When distended with sperm the epithelium appears squamous‐like. The tubuli efferentia are lined for the most part with pseudostratied ciliated columnar epithelium resting on a basement membrane. The epithelium is thrown into permanent longitudinal ridges. The epididymal tubules are lined with ciliated columnar epithelium resting on a bastment membrane.The three types of genital ducts are intermingled to some extent, but maintain a definite sequence in their connection with one another. The rete testis drains into the tubuli efferentia, and the latter into the epididymal tubules. These drain into the vas deferens.
Oogenesis of Meretrix casta (chemnitz) with a note on the nature of the contents of neutral red vacuoles
Authors: Subramaniam M. K. 
Published: February 2005

AbstractThe Gelgi bodies in Meretrix casta being visible in fresh eggs, an attempt was made to elucidate the nature of the contents of neutral red vacuoles. These are neo‐formations which arise on treatment with neutral red Ringer. As recent researches have shown that neutral red forms compounds with enzymes, it is suggested that the new vacuoles in Meretrix are visible products of the attempt of the Golgi apparatus to eliminate neutral red which is a foreign substance to the egg. The function of Golgi bodies in the control of cell metabolism by production of intra‐cellular enzymes is discussed.
Spermatogenesis of the prawn, Palaemon lamarrei
Authors: Nath Vishwa 
Published: February 2005

AbstractThe spermatozoon of Palaemon lamarrei is like a cricket ball having a small hole at the top. The outer leather covering of the ball represents the nucleus and the internal stuffing the cytoplasmic vesicle, in the formation of which almost the whole of the cytoplasm of the spermatid along with its mitochondrial and Golgi material is sacrificed. The hole is very efficiently plugged with a ring‐like centrosome, which gives off inward a large number of axial filaments radiating through the vesicle toward the nucleus and outward a long prominent spine ending into a fine point. The acrosome is conspicuous by its absence. It has been suggested that, as in Paratelphusa spinigera, the cytoplasmic vesicle forms the mechanism, which is responsible for the explosion of the sperm at the time of fertilization. It has also been suggested that the bizarre structure of the sperm is closely associated with the necessity of ensuring the safety of this explosive vesicle until the time of fertilization. The chromatoid bodies described by Fasten in the crayfish, Cambarus virilis, must be interpreted as the Golgi masses.
A comparative study of the chromosomes of eight genera of Indian Pyrgomorphinae (Acrididae)
Authors: Rao T. Ramachandra 
Published: February 2005

AbstractIn the spermatogonia of all the genera studied, there are nineteen rod‐shaped telomitic chromosomes, which differ considerably regarding their actual sizes in the different genera. However, an analysis of the measurements of second spermatocyte chromosomes shows that as regards proportional sizes and in seriation there is some degree of uniformity within the sub‐family. In Aularches, Atractomorpha, Chrotogonus, Colemania and Pyrgomorpha, the members of the smallest pair of autosomes appear as roundish or oval bodies and are comparable in shape, relative size and behavior with the ‘small’ dot‐like chromosomes of the general Acrididae, while in Orthacris and Zarytes they are not so and merge into the general series. The sex chromosome is the largest one in the complexes, or the second largest as in Poecilocerus. The usual forms of tetrads occur in the spermatocytes. It is found that the number of ring tetrads in any genus depends upon the length of its chromosomes; in genera with longer chromosomes there are more of them than in genera with shorter ones. While no final explanation has been offered regarding the chromosome relationship between this sub‐family and the other Acrididae, some points arising out of the present study have been briefly discussed, and it is shown that a simple process of elimination of two pairs is not sufficient to explain the smaller chromosome number in Pyrgomorphinae.
The development of the swim bladder of the Atlantic salmon
Authors: Hoar William S. 
Published: February 2005

AbstractThe anlage of the swim bladder of the Atlantic salmon arises as a small mass of undifferentiated cells resting dorso‐laterally on the posterior wall of the fore‐gut. This mound of cells is proliferated from the narrow band of mesoderm which lies between the epithelium and the serosa of the alimentary canal. The concentration thus formed elongates slowly for 11 weeks. At the end of this time an evagination from the lumen of the right side of the oesophagus grows into it. This tube commences to elongate rapidly just previous to the time of hatching, and reaches the posterior end of the body cavity at approximately the time when the young salmon emerge from the gravel. Throughout the fresh water life of the fish this organ is a relatively large thin walled sac, lying dorsal to the body cavity. Microscopic examination reveals layers typical of those of the digestive tract.
The structure of the nasal cavity in chamaeleo chameleon (Linnaeus)
Authors: Haas Georg 
Published: February 2005

AbstractThe nasal capsule of the chameleon differs greatly from that of other lizards in several respects. Cartilage is extremely persistent, particularly in the roof. The anterior chamber is produced backward to form an accessory posterior chamber. This posterior extension lies lateral to the olfactory chamber, from which it is incompletely divided by a longitudinal fold which may represent the normal concha.The organ of Jacobson is extremely reduced and occupies an abnormal position with relation to other structures. The olfactory nerves and their branches are much reduced, and the olfactory epithelium is poorly developed. The chameleon is at best a microsmatic animal.
The liver‐blood fluid exchange and the morphology of hepatic cell mitochondria
Authors: Kater J. McA 
Published: February 2005

AbstractThis work was undertaken in an effort to determine the reason why the hepatic cell mitochondria of some animals show a structural response to adrenalin while others show no such reaction.It was found that those animals whose mitochondria are altered by adrenalin undergo a relatively great increase in the percentage of water in the liver. This acquisition of fluid by the liver is accompanied by a disturbance of the cell‐plasma ratio of the blood. Those species whose mitochondria show no reaction to adrenalin have no change of volatile liver water, haematocrit reading, and probably have no change of total blood volume.
Certain reproductive organs in the Neritidae
Authors: Andrews E. A. 
Published: February 2005

AbstractDescriptions and figures of the subordinate sex‐organs are given for thirty species taken at random throughout the entire family.It is found: that the higher genera have organs not present in the lower; that they have a storage sac for mineral particles to be added to the secreted capsules within which the eggs will develop; that the anus is more or less fused to the mouth of the oviduct to allow of easy passage of the above materials from anus to oviduct; that spermatophores grade from simple elongated tubes of the lower to stout double tubes with various forms, with spicules, or with spirals, in the higher forms; that the sacs for holding the spermatophores may be simple, when the spermatophores are cast out after discharge, but are more evolved when spermatophores are to be permanently retained and digested; that while lower forms have no sex organs upon the head, peculiar organs occur in the higher genera, in one or both sexes.These organs have value as aids in classification of genera within the family Neritidae. The very marked coordination among these organs may be better understood when further observation reveals how they are used in sperm transfer.
The effect of temperature on mitochondria in liver cells of fish
Authors: MaCcardle Ross C. 
Published: February 2005

AbstractFundulus and goldfish were subjected to varying degrees of temperature from 0° to 60°C. Heat rigor and lethal temperatures (37° to 40°C.) cause mitochondria to vesiculate, fragment, globulate and dissolve. The Golgi apparatus becomes swollen, breaks into small dictyosomes which migrate to the peripheral cytoplasm, and dissolves. Osmicated fat increases in amount. The vacuoles (vacuome) increase in number. Evidence is presented to show that dissolution of mitochondria takes place by three distinct methods; namely, (1) vesiculation, (2) fragmentation, (3) globulation. The mixochondriome hypothesis is proposed. This is based on the idea that the mitochondria differ in their chemical constitution, an idea which is supported by the fact that each kind of mitochondrion shows a characteristic manner of dissolution. It is believed that the semi‐lunar vesicles of goldfish liver cells are not of mitochondrial origin, and that they and the Golgi apparatus are concerned in fat formation.