bluuebunny/crossref_metadata_2025_split huggingface dataset:
The septomaxillary of the Amphibia Anura and of the Reptilia. II
Authors: Lapage Enid Oldham 
Published: February 2005

AbstractThe septomaxillary is described in certain anurans and in some of the reptiles in which it occurs. In urodeles and some anurans this bone arises by ossification of the nasal cartilages. Lack of embryological material has prevented the verification of this in the young stages of the reptiles. Adult reptiles have been examined, and in these the bone appears to be and has often been described as a ‘membrane bone.’ It is suggested, however, that the septomaxillary is originally a ‘cartilage bone,’ and that in the reptiles additional membrane bone layers form its main part and obscure its cartilaginous origin. The infolding of the bone in the anurans and reptiles until it lies in close contact with the nasal septum, and thereby loses contact with the external nasal structures, appears to be correlated with the loss of the external nasal muscles. This loss in its turn results from the adoption of terrestrial life and consequent changes in the respiratory mechanism.
The significance of the ultimobranchial body (postbranchial body, suprapericardial body): A comparative study of its occurrence in urodeles
Authors: Wilder Magel C. 
Published: February 2005

AbstractThe significance of the ultimobranchial body has been the object of a comparative study of the structure in twenty‐four species of urodeles. In nineteen of these it has not hitherto been described.Caudal to the last branchial arch, it develops as a thickening and later as an outpushing from the ventral wall of the pharynx. Due to the growth mechanics of the region, it comes to lie obliquely to the pharynx, ventral to it, and dorsal or dorsolateral to the pericardial cavity in its anterior region. It persists throughout life as an epithelioid or epithelial structure, usually of irregular shape, frequently containing vesicles; in some cases it exhibits a considerable amount of secretory activity of variable quality. Except in Amphiuma and Necturus, where it is regularly paired, and in occasional instances in individuals of other species, where it occurs on both sides, it is usually present on the left side only. Its occurrence is constant in all of the species of urodeles for which it has been examined.It is variable in size, form, and position. This, together with the quite inconstant indication of secretory activity, marks it as a structure of little or no physiological significance. ‘Colloid’ is, however, present in some instances, and hence a comparison with the thyroid was considered.
Growth and maturation in the parthenogenetic and sexual eggs of Moina macrocopa
Authors: Allen Ezra , Banta A. M. 
Published: February 2005

AbstractFrom a study of over 1000 mothers, the female chromosome number appears to be 2N = 22; N = 11. The male number has not been exactly determined, but is presumably not haploid. Only one maturation division occurs in the parthenogenetic egg, and the authors have seen only one in the sexual egg. During the growth stages of the eggs, the chromatin is totally obscured by a large amount of deeply staining nucleolar material which exhibits several phases. Ultimately, this material is apparently absorbed into the ooplasm. Just before the egg is laid, the ovoid chromosomes, in late prophase or in metaphase, are seen in a germinal vesicle situated always at one side of the egg. The maturation division occurs immediately after egg laying. A degenerate body, hitherto undescribed, is noted in the ripe parthenogenetic egg, situated at the pole opposite the germinal vesicle. It is believed to arise by reorganization of nucleolar substance. The body in the sexual egg desribed by Weismann and Ishikawa ('91) as the Paracopulationzelle is noted and its interpretation by these authors questioned, but, for lack of sufficient evidence, no counter‐explanation is offered. The possible relation between experimental sex control and the time of maturation division in the parathenogenetic egg is discussed.
A connecting link between the Annelida and the Echiuroidea (Gephyrea armata)
Authors: Heath Harold 
Published: February 2005

AbstractDuring the course of a hydrobiological survey of Monterey Bay, California, a series of pelagic organisms was taken at a depth of approximately 350 M., which appears to be a link connecting the Echiuroidea (Gephyrea armata) on the one hand and the polychaetes on the other. The range in body length is from 5 mm. to 27 mm.; and in an extended condition the anterior end of the body, with its palps and cirri, bears a close resemblance to a nereid. The supra‐oesophageal ganglia and the ventral nerve cord, with eleven pairs of ganglia, are also strikingly annelidan in character. On the other hand, the spacious coelom, communicating with the exterior by a pair of anterior nephridia, allies it with the gephyreans. The same is likewise true of the gonad, which arises from the coelomic epithelium surrounding the genital vessel. The various systems are described in detail, and their resemblances to those of other annelids are indicated. This new species, Poeobius meseres, is made the representative of a new family, the Poeobiidae, which, provisionally at least, is included in the Echiuroidea.
Variation in spermiogenesis in the teleost family Cottidae
Authors: Hann Harry W. 
Published: February 2005

AbstractIn the family Cottidae there is a greater variation in the shape of the sperm than has been found, with one exception, among all the remainder of the teleosts. There is an oval and a slender type of sperm with intergrading forms. The oval and the slender types vary, so that there is a more or less complete gradation from a nearly round, disc‐shaped sperm to a slender, flattened sperm.Spermatid masses have been found only in some of the oval sperm forms. They have been found in seven species and subspecies of the genus Cottus and in three other genera of the family, but have not been found outside of the Cottidae. They occur in widely separated places, such as Norway and China, and in both fresh‐ and salt‐water forms. In Cottus bairdii they are not found in all localities, their presence apparently being due to some external factor, perhaps temperature. It is highly probable that further investigation will show that in other species of the family, also, spermatid masses are present in some localities and not in others.
Golgi bodies, vacuome, and mitochondria in the salivary glands of the Chironomus larva
Authors: Beams H. W. , Goldsmith J. B. 
Published: February 2005

AbstractOur observations confirm the recent findings of Krjukowa ('29) on the specific character of the Golgi material in the salivary glands of the Chironomus larva and are therefore in disagreement with the findings of Parat and Painlévé ('24).The Golgi material in the salivary glands of the Chironomus larva is present as discrete bodies having the form of crescents, rings, and rods. These are evenly deposited throughout the gland and show no makred variation in number at different stages of the physiological activity of the gland.The mitochondria are present in the form of filaments frequently concentrated in the area surrounding the nucleus and at the periphery of the cell.Neutral‐red staining was never observed to color the Golgi bodies. It is suggested that the neutral‐red bodies may represent the secretory material. However, it is clear that, whatever the significance of the neutral‐red bodies, they are not Golgi material. Accordingly, this evidence supports the view that the Golgi apparatus, mitochondria, and neutral‐red bodies are morphologically distinct structures in the cells of the salivary glands of the Chironomus larva.
The origin of the germ cells in Amblystoma maculatum
Authors: McCosh Gladys K. 
Published: February 2005

AbstractThis study is based upon a close series of ontogenetic stages from cleavage until after metamorphosis.The so‐called primordial germ cells, first differentiated in the lateral mesoderm, are traced to a definitive position in the genital anlagen. Careful counts of these demonstrated that they exist in larger numbers in the younger stages and that few of them ever reach the genital anlagen where they may form a small portion of the propagative cells.Evidence is presented that the majority of the germ cells are of somatic origin. From the earliest appearance of the indifferent gonad certain cells in the germinal epithelium have been observed which were increasing markedly in size and undergoing the various changes necessary in the transformation of small cuboidal or spindle‐shaped peritoneal cells with oval nuclei into large germ cells with immense polymorphic or lobate nuclei. These cells are abundant in all older individuals. All the successive stages in the evolution of a somatic cell into a reproductive cell, involving as it does an increase in size, changes in shape, and a new distribution of chromatin material, are demonstrated.
An investigation of the nervous system as a possible factor in the regulation of ciliary activity of the lamellibranch gill
Authors: Lucas Alfred M. 
Published: February 2005

AbstractCertain variations of ciliary activity in the lamellibranch gill occur which are an intrinsic part of the gill tissue and which are due to causes other than environmental changes. Experimental and morphological evidence indicates that the central nervous system is not involved in the production of these variations.A comparative study of laterofrontal and lateral ciliated cells leads to the conclusion that the coordination impulse passes through the cytoplasm of the cell and that the velocity of the propagation wave is influenced by the number of cell walls per unit length through which it passes. It is suggested that the ciliary rootlets in the laterfrontal cells, due to their arrangement bring the impulse simultaneously to both rows of cilia within a single cell.
The distribution of the branchial nerve in Mytilus edulis and its relation to the problem of nervous control of ciliary activity
Authors: Lucas Alfred M. 
Published: February 2005

AbstractThe branchial nerve of Mytilus edulis, traced by means of serial sections, has been found to be limited entirely to the epithelial and connective tissues bordering the axis of the gills. Most of the numerous branches which originate from the branchial nerve extend posteriorly and lie close to the interfibrillar matrix of the connective tissue which supports the epithelium of this region. Fibers of these nerves have been traced to this epithelium.The chitinous supporting structures of the gills lie in close proximity to these nerves, yet neither nerves nor nerve fibers have been observed to penetrate them. Moreover, a careful study of the gill tissues fails to reveal the presence of structures which might be interpreted as nerves or nerve fibers.Since no innervation of the gills has been demonstrated, it seems probable that the ciliary activity of the gill epithelium is not regulated by means of fibers connected with the central nervous system.
The effects of vitamin‐E deficiency on the development of the chick
Authors: Adamstone F. B. 
Published: February 2005

AbstractIn an investigation of the hatchability of eggs from hens fed on a diet deficient in vitamin E Card found that all embryos from these eggs died during development. Study of these chicks showed that a variety of conditions were responsible for death:During early development the rate of growth and differentiation was definitely slower than under normal conditions, but malformations were rare. Some embryos died during the first two days, due to disintegration of the circulatory system or its failure to become established. At the end of the fourth day there was a definite critical period which few specimens survived and by this time distinet pathological conditions had arisen in extra‐embryonic structures. These involved wiping out of the vitelline circulation by establishment of a lethal ring in the blastoderm. This structure was produced by intensive cell proliferation in the mesoderm which resulted in choking out vitelline blood vessels and their subsequent degeneration. It also caused obliteration of the exocoele, with consequent failure of the allantois to expand. In addition, many embryos showed profuse haemorrage into the exocoele. The source of bleeding was most frequently in the atrium of the heart, and at the actual rupture peculiar cells occurred which were probably histiocytic mesenchyme cells.Although death was due directly to causes enumerated above, the ultimate responsibility rests upon conditions set up by them, namely: starvation, asphyxiation, and loss of the medium (blood) by which to carry on metabolic exchange.
Keimbahn determinants and continuity of the germ cells in Sphaerium striatinum (Lam.)
Authors: Woods Farris H. 
Published: February 2005

AbstractDuring oogenesis granular mitochondria become concentrated in the proximal portion of the oocyte and remain concentrated in the line of cells that gives rise to the germ cells. Two cells of characteristic structure, appearing at gastrulation one on either side in the mesoderm, contain this mitochondrial cloud. All functional germ cells seem to be lineal descendants of these two primordial germ cells. The cloud disappears during gonad formation, but reappears in oocytes of the next generation. Except during meiosis and fertilization the germ‐cell cycle is traceable from fertilized egg to sexual maturity. Details of meiosis and chromosome number were not ascertained.Capacity for producing germ cells in Sphaerium is traceable from a definite region in the egg to primordial germ cells through a localized cloud of mitochondria in the mature ovum and certain cells of cleavage stages. Mitochondria, therefore, serve as a Keimbahn determinant in the sense that they mark a region of oocyte cytoplasm destined for cytoplasm of primordial germ cells. They are not considered causal factors in production of germ cells, but are probably storage products persisting unused in the egg and in cleavage cells having lower metabolic rates. Disappearance of these mitochondria during gonad formation is explained by their dispersal among a number of cells and by their utilization in furnishing energy and material for production of new cells.
A microscopical study of glochidial immunity
Authors: Arey Leslie B. 
Published: February 2005

AbstractGlochidial cysts on the gills of immune fishes form in the same manner as normal ones, but they tend to grow larger and become more irregular. The increased thickness is due to additional cellular connective tissue in the wall. The gill tissue indicates the existing biological incompatibility only by the presence of eosinophiles, extruded chromatin spherules, and eosinophilic plastids.In natural, or racial immunity many glochidia are promptly destroyed by cytolysis, accompanied by an invasion of host cells. These disintegrating glochidia may occur in close proximity to unaffected glochidia and apparently are merely less resistant individuals that succumb to a critically adjusted reaction.In both natural and acquired immunity the normal retention of glochidia and the accompanying metamorphosis are replaced by premature shedding. After the first day, the cyst thins by the removal of stroma cells back into the filament until the wall is reduced to a thin envelope. Both intact and destroyed glochidia, and apparently their cyst coverings, are sloughed at about the second day. Repair of the resulting notched filament is prompt.
The effects of x‐rays on regeneration in Tubifex Tubifex
Authors: Stone Raymond G. 
Published: February 2005

AbstractPosterior regeneration in Tubifex is inhibited by suitable radiation with x‐rays. Only a small knob is formed at the cut surface by rearrangement of the terminal region of the old body tissues. Location of the cut within the segment and repeated removals of segments within the posterior three‐fourths of the body do not change this result. The worms are as though ‘castrated’ against regeneration. Normal worms regenerate readily under similar conditions and replace lost segments within thirty‐five days. Mesodermal tissues in normal regenerating Tubifex are formed from neoblasts, which arise from peritoneal cells upon the posterior faces of septa near the cut, migrate to this wound surface, and differentiate into new structures. After radiation no neoblasts arise from peritoneal cells and there is no mesodermal regeneration. No changes, other than failure to form neoblasts, can be observed in the peritoneal cells. Migrating neoblasts are destroyed within a few hours by similar radiation.Epithelial tissues are also affected by x‐rays, as shown by absence of mitoses and failure of regeneration in ectodermal and endodermal epithelia. During normal regeneration cells which form these epithelia and certain muscle fibers arise by proliferation from the epidermis and intestinal lining in the regenerating region, as shown by numerous mitoses in these layers. Failure of regeneration in radiated worms is thus related to lack of cells which are present in normal regeneration.
The genitalia of the Indian mollusk Indoplanorbis exustus
Authors: Baker Frank Collins 
Published: February 2005

AbstractThe molluscan genus Indoplanorbis is shown to differ markedly from all other members of the family Planorbidae in the generative complex, the vas deferens being encased in a long, flexible tube in which it is freely movable. The preputium of the male complex is shown to be completely evertible from the male opening and to act as a male copulatory organ. The presence of a single, heavy penial retractor innervated by an equally strong nerve is indicated. Comparisons are made with the genitalia of the European Coretus and the American Helisoma showing fundamental differences in the generative apparatus of the three groups. Indoplanorbis is most closely related to Coretus, the vas deferens of that group being also encased in a tube. Helisoma differs from both of these genera, the vas deferens not being encased in a tube and is of the same diameter throughout its length.
The homologies of the flexor and adductor muscles of the thigh
Authors: Haines R. Wheeler 
Published: February 2005

AbstractThe literature relating to the flexor and adductor muscles of the thigh and their nerve supplies, in Sphenodon, the lizards, crocodiles and mammals was correlated and new dissections made of animals belonging to the last three groups. All of these muscles can be traced as individual entities from animal to animal without loss or addition to their number, although splitting may occur. The attachments of the muscles and their relationships to one another and to the two heads of the gastrocnemius are the same in all the reptiles studied. In the mammals one group, including the adductor longus and magnus and the retractor femoralis, has migrated from the tibia between the two heads of the gastrocnemius onto the femur, and another from the ilium onto the vertebrae, the one migration being caused by expansion of the gastrocnemius, and the other by expansion of the gluteal muscles. A new lateral flexor mass has been formed from part of the reptilian ilio tibialis by migration down the fibula. The nerve supplies of the various muscles are not constant when traced from group to group, and it is suggested that a muscle receives its nerve supply from the nerve nearest to it in embryonic development, so that when a muscle has migrated the nerve supply is no longer a reliable guide to its homology.
The cytology of the corpora lutea of the ewe
Authors: Warbritton Virgene 
Published: February 2005

AbstractThe cytology of corpora lutea of non‐pregnant ewes is described with reference to the origin, structure, fate, and function of these organs. The lutein cells, characteristic of corpora lutea, are derived from the cells of the stratum granulosum of the Graafian follicle; connective‐tissue cells, embryonic cells, and non‐striated muscle cells, from the theca interna; and erythrocytes, leucocytes, and histiocytes, from the blood stream. The lutein cells undergo changes in size, nuclear structure, and cytoplasmic inclusions correlated with the period in the estrous cycle and disappear during retrogression. Although secretory products have not been identified, a secretory function is postulated on the basis of the structure of the cell.
The idiochromosomes of an earwig, Labidura riparia
Authors: Asana J. J. , Makino Sajiro 
Published: February 2005

AbstractThe diploid number of chromosomes of a species of Indian earwigs, Labidura riparia, is fourteen; six pairs of autosomes with X and Y idiochromosomes for the male; six pairs of autosomes with X and X for the female.The chromosome distribution is normal, and constant for all the individuals studied.X and Y are derived from a single chromatin nucleolus of the early growth period which assumes a clavate form later, and remains in the same form till the metaphase of the primary spermatocyte is reached.
Development of the sense organs of the larva of Botryllus schlosseri
Authors: Grave Caswell , Riley Gordon 
Published: February 2005

AbstractA study of the development of the sense organs of the larva of Botryllus schlosseri to determine, if possible, any homologies between its sense organs and those of other types of ascidians such as Molgula and Ammaroucium, which have sense organs structurally very different.The statolith appears in the Botryllus embryo as a single club‐shaped cell. The lightsensitive organs have their primordia slightly later as five small filaments, each developed from a ganglion cell. A cavity appears in the statolith into which the light‐sensitive filaments penetrate. Later development is concerned with pigmentation of the statolith, and a twisting process which orients it into the position in which it is found in the free‐swimming larva. The three tactile papillae develop from evaginations of ectoderm at the anterior end of the embryo. The ectodermal cells at the center of a papilla are differentiated into rod‐shaped sensory receptors and ganglion‐like masses of nerve tissue. Nervous connections are established between these peripheral ganglia and the central nervous system.Results of the investigation indicate that the statoliths of the different ascidian larvae are homologous; the direction eyes probably are not, but have evolved independently from a light‐sensitive area in the primitive larva of a common ancestral ascidian. The larvae of Molgula and Ammaroucium possess no structures comparable to the sensory papillae of Botryllus.
The development and structure of the eyes, ocelli, of the female black scale, Saissetia oleae bern
Authors: Marshall William Stanley 
Published: February 2005

AbstractThe female black scale possesses a pair of lateral ocelli. Each develops as a small disc of enlarged hypodermal cells which increases in size and invaginates. The disc finally becomes cut off from the hypodermis to form a vesicle lying between the regular hypodermis and the lateral margin of the brain. The vesicle becomes differentiated into two parts. The outer group of cells forms the vitreous body, the inner group gives rise to the retina. The vitreous body soon begins to secrete the lens which, during embryonic life, becomes biconvex. Pigment granules form only in the retinal cells; at first yellow, later black. The ocellus of the first instar is similar to that of the embryo. During first and second ecdyses the old lens is cast off and a new one secreted by the vitreous body. A large, irregularly shaped crystalline body forms between the vitreous body and the retina. The ocellus is of four parts: lens, vitreous body, crystallin body and retina. Retinal cells are at first nucleated but the nuclei probably pass to the nerve fibers each one of which is connected to a retinal cell. The ocellus does not change in structure throughout the life of the insect but finally disintegrates. The disintegration begins on the inner surface of the lens. Ocelli developed in the embryo remain unchanged throughout the insect's life.