bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of the ovary in the grasshopper, Melanoplus differentialis (acrididae; orthoptera)
Authors: Nelsen Olin E. 
Published: February 2005

AbstractEach indifferent genital rudiment in the grasshopper embryo is composed of the following: (1) a terminal filament membrane; (2) an epithelial plate of indifferent cells, the dorsal cell mass; (3) the central cell mass containing germ and indifferent cells; (4) the ventral cell strand, and, (5) a delicate, investing membrane, the outer limiting membrane. It is roughly spindle‐shaped in transverse section and extends from the first to the eighth abdominal segments.In the sexual differentiation of the genital rudiment the dorsal cell mass is retained as a definite embryonic rudiment in the female, but becomes an indistinguishable part of the central cell mass in the male.Ovarian development is initiated in the dorsal cell mass area, where cell aggregations are formed. Each aggregation is ultimately surrounded by the ingrowing outer limiting membrane to form distinct cellular columns. A latero‐ventrad extension of this ingrowing process into the central cell mass continues the column formation process into the latter and results in the formation of a distally tapering structure composed of indifferent cells distad and germ cells and indifferent cells proximad. This structure constitutes the rudimentary ovariole which finally differentiates to form the terminal filament, germarium, and vitellarium.The ovarian portion of the oviduct and the tubular connection between the ovariole and oviduct are differentiated from the ventral cell strand.
The developmental anatomy of male genitalia in Melanoplus differentialis (acrididae) orthoptera)
Authors: Else Frank L. 
Published: February 2005

AbstractAn investigation has been conducted to ascertain the relationship of certain structures in the embryo of the grasshopper known as Melanoplus differentialis with reproductive organs in the adult male.The order of development of these structures was traced through the entire life history.It was determined that they are the rudiments of certain reproductive organs and that the knowledge obtained serves as an aid in more accurately classifying insects.
The mesodermal relations of the pars buccalis of the hypophysis in the duck
Authors: Friedman Bernard 
Published: February 2005

AbstractThis paper describes the cellular relations between the prechordal mesoderm and the hypophyseal analage in duck embryos from the first to the eighth day of incubation.At nineteen somites the ectoderm destined to form hypophysis is seen as a plate of cells lying under the mesodermal mass anterior to the notochord. It extends anteriorly in intimate contact with the base of the forebrain, and posteriorly for about the same distance to the oral membrane. Following the lateral growth of the prechordal mesoderm and the rapid overgrowth of the forebrain, Rathke's pouch is definitely outlined. The upward expansion of the pouch, concomitant with the lagging of some of the prechordal mesoderm in the midline, effects a very close relation between these cells and those at the tip of the pouch. With the lateral expansion of the premandibular head cavities, some of the mesoderm adheres to walls of Rathke's pouch in the form of rods or knobs. As development proceeds the inherent growth tendencies of ectoderm and mesoderm express themselves differently and the rods or knobs become constricted off from the pouch, forming in its vicinity vesicles which exhibit a definite lumen.The question of an entodermal contribution to the hypophysis in this form is briefly considered.
Cytological studies of the epidermis of Rana pipiens and Rana clamitans tadpoles, with special reference to the figures of Eberth
Authors: Weed Isabelle Gifford 
Published: February 2005

AbstractThe conspicuous intracellular fibers (figures of Eberth) which are present in the basal epidermal cells of Rana pipiens and Rana clamitans tadpoles are thought to be connective tissue branches from the corium. They are not believed to represent fused mitochondria as concluded by Saguchi ('13). Their probable function is to furnish support to the basal epidermal cells and to strengthen the connection of the epithelial layer to the corium.It is believed that fully developed tadpole skin, before the period of metamorphosis has begun, consists of only two layers of cells, although there may appear to be more. Each of these layers is believed to be self‐maintaining by mitotic division within the individual layer. The basal layer apparently does not furnish cells to the outer layer, nor was any evidence found that the outer layer is sloughed during the larval period.
The osteology of the haplimous fish Novumbra hubbsi schultz with comparative notes on related species
Authors: Chapman Wilbert M. 
Published: February 2005

AbstractThis paper is an attempt to clear up the confusion concerning the osteological relationships among the Haplomous fishes.The osteology of Novumbra hubbsi was worked out by the dissection of numerous specimens. The various skeletal features found were compared with the osteology of Umbra limi, U. pygmaea, U. crameri, and Dallia pectoralis.A description of each skeletal element of Novumbra was made, followed by a description of the chief differences between it and the same structures in Umbra and in Dallia. No constant osteological differences were found between Umbra limi and U. pygmaea, and very few between these two species and Umbra crameri. Novumbra and Umbra have more in common with each other than either does with Dallia or Esox. The presence of postorbitals, postcranials, and the shape of the secondary shoulder girdle in Novumbra show it to be also closely related to Dallia and Esox.The relationships of the various forms are summarized in a synoptic key which lists the following groups: Order Haplomi. Superfamily I, Dallioidea; Family Dallidae; Genus and species, Dallia pectoralis. Superfamily II, Umbroidea; Family 1, Umbridae; Genus and species, Umbra limi, U. pygmaea and U. crameri; Family 2, Novumbridae; Genus and species, Novumbra hubbsi. Superfamily III, Esocoidea; Family Esocidae; Genus, Esox.
Insect development. VIII. Maturation and early development of unfertilized grasshopper eggs
Authors: King Robert L. , Slifer Eleanor H. 
Published: February 2005

AbstractMaturation and early cleavage in unfertilized Melanoplus differentialis eggs have been followed with material secured immediately before as well as after oviposition, and (1) fixed at once, or (2) held in an incubator at 25°C. and, subsequently, fixed at selected intervals. Eggs ready to be laid were all found in the metaphase of the first maturation division. The second polar body is given off (at 25°C.) within 5 to 7 hours after laying. Meiosis appears to be unaffected by the absence of the sperm nucleus and proceeds at the same rate as in fertilized eggs. No morphological differences could be found between the process here and in eggs from mated females.During early cleavage, or later, the diploid number of chromosomes may be restored in some (or perhaps all) cells of the embryo.Development begins in the greater number of these unfertilized eggs but is successfully completed in only a very few.
A comparative study of the hyobranchial apparatus and throat musculature in the plethodontidae
Authors: Piatt Jean 
Published: February 2005

AbstractThe hyobranchial apparatus and throat musculature of the plethodontid salamanders are examined. The interhyoideus is thought to be the homologue of the intermandibularis posterior and the posterior part of the intermandibularis anterior. The quadrato‐pectoralis is found only in Desmognathus (Leurognathus?), and Aneides. Its presence in the former is a primitive condition; in the latter, secondary. The gularis had its phylogenetical origin as a slip from the quadrato‐pectoralis. The lingual cartilage is found only in Gyrinophilus, Pseudotriton, Eurycea, and Manculus. It is the homologue of the [sehnenplatte] of Salamandra; not the otoglossal. The presence of the suprapeduncularis and the absence of the genioglossus is not peculiar to adult free tongued genera. The anatomical evidence allies Batrachoseps with Hydromantes and Oedipus. The latter two genera are derived from ancient Plethodon stock, not from Gyrinophilus stock. Stereochilus, Typhlotriton, and Typholomolge are the degenerate descendants from ancient Gyrinophilus stock.
The excretory system of the trematode, Typhlocoelum cucumerinum, with notes on lymph‐like structures in the family Cyclocoelidae
Authors: Willey Charles H. 
Published: February 2005

AbstractThe exeretory system of Typhlocoelum cucumerinum consists of three pairs of longitudinal channels communicating by a single ventral vessel with the excretory vesicle. Branches subdivide extensively and anastomose forming a dense network of tubules throughout the body. The vessele possess many of the features characteristic of lymph systems as described in amphistome trematodes. They have cuticular walls, come into intimate association with the intestine and contain a granular coagulum and cellular elements suspended in the lumen. The single system of vessels appears to be functioning as a combined lymph and excretory system. Typhlocoelum americanum Manter and Williams ('28) is regarded as a synonym of Typhlocoelum cucumerinum (Rud. 1809).
The early development of the hypoglossal musculature in the chick
Authors: Hunter Russell Palmer 
Published: February 2005

AbstractThe hypoglossal downgrowth is initiated at about the twenty‐somite stage, as ventral extensions from the postotic (occipital) myotomes 3 and 4. At thirty somites, occipital myotomes 2, 3 and 4, and cervical 1 have developed ventral processes. These descending processes with contributions from posterior myotomes later form a common condensed area below myotomes 2 to 7, the submyotomic tract. There develops from this a cord of mesoderm, the hypoglossal cord or downgrowth.The anterior postotic myotomes are classed as indirect (numbers 1, 2, 6 and 7) or direct (numbers 3, 4 and 5) contributors to the hypoglossal downgrowth.Mechanical factors associated with this growth process are discussed.The hypoglossal nerve at 75 hours has six roots, four occipital (numbers 1 to 4) and two cervical. The first two occipitai roots fail to keep pace in development and are subsequently lost. A transïtory connection of the third cervical to the hypoglossal nerve is demonstrated at the age of 5 days. At 6 days the first occipital root is reduced to scattered fibers, the remaining occipital roots, numbers 2 to 4, increase in size, cervicals 1 and 2 join the hypoglossa.The correspondence of the myotomes providing the contributions to the hypoglossal cord and the nerves providing the major contributing roots of the hypoglossal nerve is commented on.
The postembryonic history of the somatic musculature of the dragonfly thorax
Authors: Maloeuf N. S. Royston 
Published: February 2005

AbstractFrom the first larval instar until the time of the final transformation into the adult the thoracic muscles are numerically the same. The muscles increase in fiber number with the growth of the larvae. There are two types of larval muscles: a. functional (striated and of considerable diameter) b. non‐functional (unstriated and of narrow diameter). The non‐functional muscles are mainly the prospective wing muscles of the adult. They grow most in diameter at the time of the final transformation. The positions of attachment of both types of muscles undergo no marked replacements during transformation, although the skeletal parts to which they are attached may become greatly modified. The larva has numerically more muscles than the adult. Extensive obliteration of the trunk leg muscles and of some neck muscles takes place. The intrinsic leg muscles of both the larva and the adult are the same.There are no anlagen of the adult muscles in the larval labium, and myoblasts probably form the adult musculature of this organ.The wing muscles of adult Anisopterid dragonflies insert close to the articulations of the wings on apodemes arising from membranes, or on discs arising as internal invaginations of detached, lateral, tergal plates.During the metamorphosis of its musculature, a dragonfly exhibits every essential phenomenon that a so‐called ‘holometabolic’ insect does.
Further studies in modified mitosis
Authors: Stough Howard Brown 
Published: February 2005

AbstractIn a paper published by the author in 1931 there was described a process of cell division called ‘modified mitosis.’ The present report adds quantitative studies of the process and a general evaluation of it and its role in the development of the embryo. Cell counts were made in various stages of chick embryos and the mitotic indices determined. In no cases can these mitotic indices account for the growth which the cell counts indicate. Periodicity in cell division in the chick cannot be established. Modified mitosis appears after careful study to be fundamentally mitotic in nature. Actual division of chromatin, nucleus, and cytoplasm occurs. Modified mitosis is not amitotic in character, but it is probable that it is what has been reported in the past as amitosis. It is very doubtful whether amitosis is found in the chick or in any of the vertebrates. Modified mitosis is part of the active phase of cell division and cannot be explained away as merely resting stages containing one or two nucleoli. It is probable that the division of chromatin nucleoli cannot be accounted for on any other basis than that of modified mitosis. In modified mitosis we undoubtedly see irreversible cell differentiation. The genetic implications of this process are not yet clear. If present interpretations of modified mitosis are in error a complete revision of our ideas of typical mitosis is in order.
The neuromotor system of oxytricha
Authors: Lund Everett E. 
Published: February 2005

AbstractThe neuromotor system and associated organelles of Oxytricha have been studied in living specimens viewed with dark field illumination, and in whole mounts and sections stained with Heidenhain's hematoxylin or Mallory's stain. Microdissection has also been used in some cases.The neuromotor system has been found to consist of the adoral membranelles and coordinating fibrils, the undulating membrane and its basal fibril, two sets of cytostomal fibrils and two sets of postesophageal fibrils. The anal cirri may possibly be involved in the complex. No neuromotorium seems to be present.Motor and feeding organelles not morphologically connected with the above system are eight frontal and five ventral cirri, and a varying number of marginal cirri. The anal cirri, if not connected with the neuromotor system, would be included here. The minute structure of each type of cirrus has been studied, and the action and probable function has been determined from studies on normal, anesthetized, and dissected individuals. A brief comparison is made between the neuromotor system and organelles of Oxytricha and those of Euplotes and Paramecium that have previously been described in the literature.
The dorsal axial musculature of certain primitive permian tetrapods
Authors: Olson Everett Claire 
Published: February 2005

AbstractThe development of the dorsal axial musculature is traced from Eryops, through Diadectes, to Dimetrodon. lguana, a modern form, is used for comparison. The axial muscles of a primitive form, such as Eryops, were thick, fleshy, and metameric; those of more advanced types, such as Dimetrodon, were light, highly tendinous, and largely unsegmented. Diadectes represents an intermediate stage. The changes in the muscles and related changes in the axial skeleton are closelyassociated with the development of active, terrestrial animals.
The absorptive processes in the embryos of Parabrotula dentiens, a viviparous, deep‐sea Brotulid fish
Authors: Turner C. L. 
Published: February 2005

AbstractParabrotula dentiens is a viviparous deep sea Brotulid fish. The embryos at the 6 mm. stage are held within the ovarian cavity as are the embryos of Zoarces, the Embiotocidae, the Goodeidae, the Jenynsiidae and the Anablepidae in the later stages. The embryos of Parabrotula dentiens are equipped with external processes which are attached around the anus and to the ventral wall of the embryo for a short distance in front of the anus. The processes have a spongy connective tissue stroma and are covered with a syncytial layer. It is assumed that the processes augment the body surface of the embryos and have a nutrition‐absorbing and an oxygen‐absorbing function.
The osteology and relationships of the phallostethid fishes
Authors: Bailey Ralph J. 
Published: February 2005

AbstractTwo genera of the Phallostethid fishes were anatomized using both the clearing and the dissection methods. While resembling Poecillids and agreeing with them in numerous anatomical features, these fish are true Acanthopterygians and apparently are correctly placed by Myers in the suborder Phallostethoidea erected for them in the order Percesoces. The two divergent types of priapia found in the group are readily derivable one from the other, corresponding bone for bone. The priapial bones can be homologized with the missing pelvic fins and girdle plus, perhaps, the post cleithrum and some of the pectoral pterygials. A comparison is made between the Phallostethid priapial skeleton and the highly modified girdle complex of the Polynemids.
On the structure and function of the ascidian test
Authors: Das S. M. 
Published: February 2005

AbstractThe test consists of a clear matrix in which cells, fibrils, spicules and vascular tubes are embedded. It is supplied with two main blood vessels which ramify in the test substance and end in a large number of vascular ampullae near the outer surface of the test. Three different kinds of spicules are present. The test cells are of five different kinds. Besides these cells, the author has, for the first time in the history of our knowledge of the Tunicata, demonstrated the presence of nerve cells, nerve fibers and receptor cells in the test. The nerve cells are found throughout the test (except the foot) but are more numerous in the test of the siphons. The epithelial cells of the vascular ampullae act as receptor organs being supplied with nerve fibers that connect them with the nerve cells of the test. Receptor cells are also present in the regions of the test devoid of ampullae (except the foot). Stimuli are received by the receptor cells and conducted by nerve fibrils to the nerve cells, which are in turn connected with the nerve ganglion. The test, therefore, not only serves for the protection and attachment of the animal but also acts as a respiratory and receptor organ.
The cytology of the hypophysis cerebri of the bat
Authors: Sawyer Elizabeth L. 
Published: February 2005

AbstractA cytological study of the hypophyses of more than 100 female bats, collected at fortnightly intervals from October to April, is reported. The bats were decapitated within 24 hours after collection. and then hypophyses fixed in Champy's fluid or Helly's fluid followed by staining by the acid fuchsin‐thionin‐aurantia method of Kull.The pars distalis, pars intermedia, and pars nervosa lie adjacent to one another in the flattened gland. In some hypophyses the lumen of the original buccal evagination persists as a narrow residual cleft which may be expanded to form ciliated vesicles.Observations on cell size. nucleoplasmie ratio, degree of chromaticity in the nucleus, staining reactions of the cytoplasm and secretory granules, and the presence of chondriosomes, secretory granules, and vesicles in the cytosome are recorded. Secretory cells and histiocytes are idintified. Sceretoty cells are found in successive stages of growth, differentiation, secretion, and degeneration. Cells which have discharged their secretion apparently do not resynthesize secretory granules. Mitosis is not observed. The available evidence suggests utilization of a large supply of embryonic cells as the source of the fully differentiated cells. The cells of the pars intermedia are interpreted as potential secretory cells which do not differentiate under the inadequate nutrient conditions of that region.
The bodies of Eberth as a source of connective tissue ground substance in Rana catesbiana, Shaw
Authors: Cameron John Andrew 
Published: February 2005

AbstractThe bodies of Eberth in the skins of tadpoles appear in young stages as fine threads and develop into heavy, amorphous masses in close contact with the basal membranes of the epidermal cells. They possess extensions which pass from the epidermal cells through their membranes into the corium. During metamorphosis, when the amount of dermal connective tissue is greatly increased, the bodies disappear the more distal first and the most proximal latest. The processes which pass into the dermis are the last parts to remain visible. Examination of a series of stages suggests that they pass through the cell membranes of the epidermis and into the corium. The bodies then, may be regarded as reserve accumulations of secreted material which are used up in the formation of dermal connective tissue. This explanation accounts for three otherwise unexplained peculiarities of the skin of the developing frog: (1) the presence and growth of the bodies of Eberth; (2) their disappearance during metamorphosis; (3) the sudden large increase in connective tissue fibers of the dermis at metamorphosis.
Observations upon the aglomerular nature of certain teleostean kidneys
Authors: Grafflin Allan L. 
Published: February 2005

AbstractObservations are reported which fully establish the aglomerular nature of the kidney in the following teleostean species: Hippocampus trimaculatus, Hippocampus kuda, Hippocampus hudsonius, Microphis boaja, Batrachus grunniens and Pterophryne histrio. It is possible that we are dealing with an additional aglomerular species (Microphis sp.), but this cannot be determined from the available material. All species were taken in sea water except Microphis boaja and Microphis sp., which were taken in fresh water.
Sexual dimorphism in north American hawks I. Sex organs
Authors: Stanley Allan J. 
Published: February 2005

AbstractThe development of the gonads of the marsh hawk, Circus hudsonius, Cooper's hawk, Accipiter cooperi, and the red‐tailed hawk, Buteo borealis borealis has been investigated. The occurrence and relatively long persistence of the cortex on both testes of the marsh hawk is evidence of bilateral amphisexuality in this form. The embryonic condition of the ovaries is related to the degree of asymmetry in the adult organs. Nearly symmetrical, paired ovaries were found in three species and varying amounts of reduction of the right ovary in all others.The disappearance of the right oviduct in the ontogeny of the female red‐tailed hawk and the occurrence of accessory gonad tissue in male embryos of the same species are described and figured. The extent of reduction of the right ovary of eleven species is described, figured and classified. The following species are listed in the above order of classification: Circus hudsonius, Accipiter cooperi, Accipiter velox velox, Accipiter atricapillus atricapillus, Falco sparverius sparverius, Aquila chrysaëtos canadensis, Buteo borealis borealis, Buteo lineatus lineatus, Buteo lagopus sancti‐johannis, Cathartes aura septentrionalis, Buteo platypterus platypterus.It is concluded that two ways by which organs may disappear are realized in the right ovary and oviduct of the hawks. (1) by failure of an embryonic inductor in the case of the ovary, and (2) in the right oviduct by secondary atrophy of an originally well‐developed embryonic structure.