bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological and videofluorographic study of the hyoid apparatus and its function in the rabbit (Oryctolagus cuniculus)
Authors: Anapol Fred 
Published: February 2005

AbstractThe anatomy of the hyoid apparatus and positional changes of the hyoid bone during mastication and deglutition are described in the New Zealand White rabbit (Oryctolagus cuniculus). A testable model is constructed to predict the range of movement during function of the hyoid, a bone entirely suspended by soft tissue. Frame‐by‐frame analysis of a videofluorographic tape confirms the accuracy of the prediction through observation of hyoid bone excursion during oral behavior.During chewing, translation of the hyoid bone is diminutive and irregular, lacking a clearly discernible path of excursion. However, some movements of the hyoid occur with regularity. During fast opening, anterodorsal movement of the hyoid is interrupted with an abrupt posteroventral depression when the bolus is moved posteriorly toward the cheek teeth by the tongue. This clockwise rotation (when viewed from the right side) of the hyoid accompanies jaw opening and is reversed (posteroventral movement) for the jaw closing sequence. Lateral movements of the hyoid may be slightly coupled to mandibular rotation in the horizontal plane.The findings suggest that the hyoid bone maintains a relatively static position during the dynamics of chewing. The primary function would be to provide a stable base for the movements of the tongue. Another possible function would be to control the position of the larynx within the pharyngeal cavity. Some characteristic features of the rabbit hyoid apparatus may be consequential to relatively erect posture and a saltatory mode of locomotion.
Ultrastructure of the sensory complex on the maxillary and labial palpi of the colorado potato beetle, Leptinoarsa decemlineata
Authors: Sen A. 
Published: February 2005

AbstractSensilla on the maxillary and labial palpi of Leptinotarsa decemlineata were examined by scanning and transmission electron microscopy. There are a total of 370 sensilla on the apical tip of the maxillary palpi and 130 on the labial palpi. Four morphologically different types of sensilla are present on the maxillary palpi, three of which are common to the labial palpi. Type A sensilla, unique to the maxillary palpi, and type C sensilla have the structural characteristics of olfactory sensilla. Types B and D, with an apical pore, are considered contact chemoreceptors. Cuticular specializations, interrelationships of enveloping cells, comparative morphometry of dendrites, distribution of each sensillar type, and the predominance of olfactory sensilla are discussed in relation to feeding behavior.
Morphology of the pronephros of the juvenile brown trout, Salmo trutta
Authors: Tytler Peter 
Published: February 2005

AbstractThe pronephros in juvenile brown trout (Salmo trutta) consists of a large ovoid renal corpuscle and a pair of tubules. The corpuscle is retained for 11 months, after which the glomerulus regresses. The glomerular arteries come directly from the dorsal aorta. The interstitium is permeated with venous blood vessels that arise from the anterior cardinal veins and are closely apposed to the tubules. Two distinct segments of the pronephric tubular system are distinguished by the histological and ultrastructural features of their component cells: (1) a short, transitional neck in which cells change from capsular epithelium to columnar epithelium, typical of tubules; (2) the convoluted segment composed of cells similar to first proximal tubular cells of the opisthonephros with well‐formed brush borders, apical vesicles that vary in size and number along this segment, and lysosomes. Pinocytosis and exocytosis are also evident in this segment. The tubular system increases in length and in its convolutions until about week 9, when the opisthonephros develops. Distally each tubule connects with a Wolffian duct, with cells marked by the absence of apical inclusions and the presence of a uniform brush border, numerous mitochondria, and elaborate infolding of the basalar membrane. Nephrostomes, which are often characteristic of pronephroi, are not present. Cells with long cilia are found throughout the tubular system but are most characteristic of the neck and Wolffian‐duct segments.
A comparison of the structure of the spermatozoa and spermatogenesis of 16 species of patellid limpet (Mollusca: Gastropoda: Archaeogastropoda)
Authors: Hodgson A. N. , Bernard R. T. F. 
Published: February 2005

AbstractLight and transmission electron microscopy of the spermatozoa and spermatogenesis of 16 species (in three genera, Patella, Helcion, Cellana) of patellid limpet have shown that head lengths of the sperm range from 3 to 13 μm, and each species has a sperm with a unique morphology, indicating that the spermatozoa can be used as a taxonomic character. Although spermatozoon structure is species specific, five types can be recognized, based on the size, shape, and structure of the nucleus and acrosome. The occurrence of five morphological types of sperm, one of which (Cellana capensis) is particularly different from other patellids, suggests that the taxonomy of the family Patellidae be re‐examined. The morphological changes that occur during spermatogenesis are very similar in all species, although two patterns of chromatin condensation are found. Those species with sperm that have short squat nuclei (length:breadth < 3.5:1) have a granular pattern of condensation. Species with sperm that have more elongate nuclei (length:breadth > 5:1) have an initial granular phase followed by the formation of chromatin fibrils. These fibrils become organized along the long axis of the elongating nucleus. The absence of a manchette suggests that nuclear elongation is brought about from within the nucleus.
Arterial and venous vasculature of the heart of the beluga whale (Delphinapterus leucas)
Authors: Bisaillon André , Martineau Daniel , Le St‐Pierre Michè A. , Béland Pierre 
Published: February 2005

AbstractThe arteries and veins of the heart of the beluga whale (Delphinapterus leucas) are described from the dissection of nine specimens. The arterial distribution is composed of the basic mammalian pattern of two major vessels, the left and right coronary arteries, which supply the cardiac tissue. The venous drainage is provided by three major systems which are the great, middle, and small cardiac veins. The vascular characteristics of the heart of the beluga whale are the marked sinuosity of both coronary arteries and their main branches, the numerous large interarterial anastomoses between major vessels, and the duplication of vessels in parallel branches. These characteristics are discussed in functional terms and correlated with the diving ability of the species.
Multicellular complex of chloride cells in the gills of freshwater teleosts
Authors: Hwang Pung‐Pung 
Published: February 2005

AbstractMorphology of branchial chloride cells in the freshwater teleosts Plecoglossus altivelis, Cyprinus carpio, and Oreochromis mossambicus was studied by light and transmission electron microscopy. The chloride cell has an apical membrane directly in contact with the outer medium. Generally, two or more neighboring chloride cells share an apical pit, forming a multicellular complex. The chloride cells form a multicellular complex in which cells differ in cytoplasmic electron density, development of tubular system, and in cell size. Chloride cells are linked by junctions which are shallower than the tight junctions that occur between neighboring pavement cells or between pavement and chloride cells. Multicellular complexes of chloride cells create additional paracellular pathways marked apically by the shallower junctions. Since junctional structure affects transepithelial permeability, development of multicellular complexes of chloride cells in freshwater fishes may be related to the transport of some substances as in the gills of marine fishes.
The buccopharyngeal mucosa of the turtles (Testudines)
Authors: Winokur Robert M. 
Published: February 2005

AbstractGross and histological examination of all extant families of turtles revealed that the buccopharyngeal mucosa is morphologically highly varied. The tongues of aquatic species have small lingual papillae or lack them entirely, while terrestrial species have tongues with numerous glandular papillae. The pharynx and the esophagus also have papillae in some species. These either facilitate swallowing in which case they are long, pointed, keratinized, and occur commonly in marine turtles, or they are vascular and nonkeratinized, facilitate respiratory gas exchange and are found in the Trionychidae, Dermatemyidae, and Carettochelyidae. The morphology of the buccopharyngeal mucosa of turtles reflects their diet, feeding behavior, habitat, and relationships. Convergence in the morphology of the buccopharyngeal mucosa occurs among families, especially among the Emydidae and other familes of turtles. Intergeneric parallelism is also seen within the Emydidae.
Trophoblast concept as applied to therian mammals
Authors: Blackburn Daniel G. , Taylor J. Mary , Padykula Helen A. 
Published: February 2005

AbstractAvailable evidence provides little support for a recent proposal that the term “trophoblast” be applied solely to eutherian mammals. Arguments for such a restricted usage are based on a dichotomous interpretation of therian reproduction that underestimates the developmental, structural, and functional diversity of trophoblastic tissues occurring within the infraclass Eutheria. The occurrence of developmental patterns that are phenotypically intermediate between those of commonly studied eutherians and metatherians suggests that blastocyst development is not fundamentally different in marsupials and eutherians.The trophoblast of marsupials accomplishes most or all of the major functions of the eutherian trophoblast, including maternal‐fetal physiological exchange, implantation, contribution to placental membranes, steroid metabolism, and possibly, immunological protection of the conceptus. Furthermore, application of the term “trophoblast” to marsupials is consistent with present and past usage, as well as with the original definition and etymological derivation of the term. Therefore, we recommend that the term “trophoblast” continue to be applied in a functional‐morphological sense to the appropriate extraembryonic tissues of marsupials. Such use of functional (rather than taxonomic) criteria for application of this term avoids biasing interpretations of mammalian reproductive evolution.
Form and function of the tongue in agamid lizards with comments on its phylogenetic significance
Authors: Smith Kathleen K. 
Published: February 2005

AbstractThe morphology of the tongue of agamid lizards is reviewed and discussed in the context of its functional and phylogenetic significance. It is shown that in several features, including the development of the central musculature of the tongue into a ring muscle and the presence of a genioglossus internus muscle in adults, the tongue in most agamids is derived relative to that in other squamates. In some features, such as the vertical connective tissue septa, agamids share primitive features with Sphenodon. Some conditions found in agamids are also found in anoline iguanids. Two genera, Uromastyx and Leiolepis, differ significantly from other agamids in intrinsic tongue musculature.The functional significance of the unique tongue morphology is that agamids utilize a different mechanism of tongue protrusion from that of other lizards. This mechanism involves the production of force against the lingual process, leading to an anterior slide of the tongue, and is detailed in this paper. Finally, I discuss the mechanical basis for the transformation series of tongue protrusion mechanisms from agamids to chamaeleonids. It is suggested that the mechanism of tongue protrusion in chamaeleonids is not unique, but is a highly derived state of the condition found in agamids.
Intercellular bridges and factors determining their patterns in the grasshopper testis
Authors: Carlson J. Gordon , Handel Mary Ann 
Published: February 2005

AbstractIntercellular bridges joining cells contained in cysts of Chortophaga viridifasciata testes were studied with light and electron microscopy. Preparations consisted of expressed whole cells (living, or fixed and stained) as well as sections. The secondary spermatogonia of each cyst are joined centrally by persisting fused interzonal bodies (fusomes) of incompletely cleaved cells. Shifts in cell orientation during anaphase are apparently responsible for central as opposed to chain linkage of cells. In the primary spermatocytes, the central fusome is replaced by a chain linkage, apparently resulting from the breakdown of the fusome into its original interzonal body components. Intercellular bridges are also present in spermatids, but there is no evidence to indicate the time of their formation (in the immediately preceding meiotic divisions or in the secondary spermatogonial divisions). The function of the compact centrally situated fusome in the secondary spermatogonial cyst is discussed as it relates to synchrony, number of cell divisions, spermatodesm formation, and fertility.
External observations on the formation of statoblasts in Plumatella emarginata (Bryozoa, Phylactolaemata)
Authors: Mukai Hideo , Kobayashi Kumiko 
Published: February 2005

AbstractUsing laboratory‐grown colonies of Plumatella emarginata, the formation of the floatoblast and the sessoblast was studied. Both types of statoblast develop in the funiculus. Toward the termination of development, the floatoblast secretes a gas and the float chambers are filled with the gas in about 20–30 minutes. The floatoblast thus complete is separated from the funiculus. Until early epidermal‐disc‐stage, distinction between a floatoblast and a sessoblast is impossible at least morphologically. Toward the late epidermal‐disc stage, a future sessoblast becomes larger than a future floatoblast and attaches by its cystigenic side to the cystid. Very often it initially attaches to a lateral wall, then migrates to the basal wall of the cystid. Both the attachment to and the migration along the cystid wall are attained by peritoneal cells covering the sessoblast, specifically by those in the marginal zone of the cystigenic side. The sessoblast is separated from the funiculus precociously, shortly after attachment to the cystid. Then, it produces the capsule, followed by the formation of both the lamella, a homologue of the float in the floatoblast, and the attaching apparatus.Almost all polypides produce floatoblasts (up to 17 in number), but only a small portion of them produce both floatoblasts and sessoblasts. The number of sessoblasts produced by a single polypide is usually not more than 3 but occasionally reaches up to 6. When multiple sessoblasts are formed by a polypide, they are as a rule derived from primordia located adjacently on the funiculus, accordingly successively in a short period, but their arrangement on the basal wall of the cystid does not always correspond to that on the funiculus. Sessoblast formation is never associated with the death of the mother polypide. Ancestrulae derived from statoblasts never produce mature statoblasts, though may undergo gametogenesis. Several mosaic statoblasts consisting of floatoblast‐ and sessoblast‐portions were found in some species of the Plumatellidae. A primordium of the statoblast seems to have a dual ability of differentiating into either a floatoblast or a sessoblast; but little has been known about the mechanism or factors controlling the formation of these two types of statoblasts.
Ocular morphology in antarctic notothenioid fishes
Authors: Eastman Joseph T. 
Published: February 2005

AbstractBeneath the sea ice at McMurdo Sound, Antarctica, notothenioid fishes are subject to extreme seasonal variation in the annual light cycle including 4 months of continual darkness. Gross and microscopic anatomy of the eyes of 18 species revealed ocular morphology that was generally similar to that of coastal fishes elsewhere in the world, and unlike that of deep sea fishes living in perpetual darkness. The spectacle was well developed as were hyaloid arteries at the vitreoretinal interface. Fourteen species had a choroid body, and its presence was considered a primitive character state for notothenioids. The choroid body was absent in phyletically derived groups. The choroid body was especially large in Dissostichus mawsoni, the only species with a rod dominated retina. Retinae were 154–279 μm thick with layering and sublayering typical for teleosts. Although all species had both rods and cones, there was marked interspecific variation in the ratio of cones:rods and in the total number of visual cells. Non‐Antarctic notothenioids from New Zealand had more visual cells than most species from McMurdo Sound. Retinae appeared balanced for vision under dim but seasonally variable light conditions and not specially adapted to the 4‐month period of winter darkness. Retinal histology reflected the ecology and depth range of most species. Based on ecology and retinal histology, four groups of species were recognized: (1) Non‐Antarctic, (2) cryopelagic (including two visually oriented benthic species), (3) pelagic and benthopelagic, and (4) benthic.
Ultrastructure of spermatozoa of the lung fluke, Paragonimus ohirai (Trematoda: Troglotrematidae), in the seminal receptacle
Authors: Orido Yasuhide 
Published: February 2005

AbstractThe seminal receptacle of Paragonimus ohirai contains not only mature spermatozoa, but also atypical and degenerate ones, suggesting that abnormal spermatozoa are retained in this organ. The spermatozoon is of a parallel biflagellar type with cortical microtubules, consisting of the anterior region, first mitochondrial region, intermediate (amitochondrial) region, second mitochondrial region, posterior nuclear region (PNR) and tail region (TR). The first third of the spermatozoon exhibits typical undulatory movement, while the middle part shows vibratory movement. At the area between head and midsections (H‐M area) the peripheral doublets of axonemes are interrupted, and the external ornamentation is distributed widely around this portion. Throughout the immotile PNR and TR, the axonemes lack the dynein arms of their peripheral doublets. H‐M, PNR, and TR ultrastructural characteristics are specific in P. ohirai spermatozoon and seem to be closely related to its pattern of movement.
Distribution and ultrastructure of neurosecretory cells in the cerebral ganglion of the earthworm
Authors: Al‐Yousuf Shoaa 
Published: February 2005

AbstractNeurosecretory (Nsy) cells within the cerebral ganglion of Lumbricus terrestris were classified ultrastructurally. The Nsy cells within the subesophageal ganglion, nerve cord ganglion, and the peripheral nervous system were also examined. A comparative survey of Nsy cells of four other species of oligochaetes, Eisenia feotida, octolasion cyaneum, Dendrobeona subrubicunda, and Allolophora longa, was also carried out. Seven cell types (A1, A2, A3, A4, A5, C, and SEF), distinguished by special cytological and ultrastructural features, were found within the cerebral ganglion. Distribution of these cells inside and outside the cerebral ganglion was studied in detail by light and electron microscopy. The nerve terminals of each cell type were followed into the neuropile region. Exocytosis from cell bodies appears to be the main release mechanism for the Nsy granules, whereas small Nsy vesicles are released through synapses in the neuropile. Peripheral fibers of some cell types (A1, A2, and A3) extend through the capsule to the pericapsular epithelium. It is possible that Nsy cells secrete hormones from their cell bodies and peripheral processes and that their centrally directed axons release modulators/transmitters within the neuropile.
Labral glands in Centropages typicus (Copepoda, Calanoida). I. Sites of synthesis
Authors: Arnaud Jean , Brunet Michel , Mazza Jacques 
Published: February 2005

AbstractIn Centropages typicus the labrum contains two symmetric gland clusters on the right and left sides. Each cluster comprises two principal elements: a vast unit (AU) located in the anterior, distal area and a dozen smaller units (LPU) in the lateral, posterior area. All these glandular units empty through several pores situated on the labrum. In addition, other secretory units (LDU) are observed in a more dorsal and posterior zone at the level of the perioesophageal nerve ring, and hence outside the labrum itself; these LDU probably secrete through the dorsal side of the stomodeum. All the glandular units (i.e., AU, LPU, and LDU) are organized in syncytia. They have the typical ultrastructural features of a secretory system (rough endoplasmic reticulum, numerous dictyosomes, and secretory granules, the latter amassed at one pole), and several stages of activity may be characterized. The biochemical composition of the products synthesized by rough endoplasmic reticulum and Golgi apparatus is probably very complex. Mucopolysaccharides and glycoproteins both appear to be contained in a single type of grain. The mucopolysaccharides would cause agglutination of food particles carried up to the stomodeum by water currents. The glycoproteins would consist of different enzymes functioning in a preliminary digestive phase occurring before the aliments enter the midgut.
Sequence of ontogenetic development and atrophy of the oral apparatus of six anuran tadpoles
Authors: Thibaudeau D. Giselle , Altig Ronald 
Published: February 2005

AbstractThe development of the oral structures of six species of anuran tadpoles with four different types of mouth parts and the metamorphic atrophy of these structures in two species with different mouth parts are described. The oral labia of typical tadpoles, oral flaps of microhylids, and lateral oral folds ofRhinophrynusare assumed to be homologous. We also suggest that the barbels of the tadpoles ofRhinophrynusare homologs of the marginal papillae of species with an oral disc. Developmental patterns and sequences of the oral structures of all tadpoles examined follow a common pattern: stomodeal invagination, oral pad development, jaw sheeth delimitation, tooth row ridge development, jaw sheath keratinization, and labial tooth keratinization. Developmental patterns remain constant, while interspecific differences are apparent because of truncations of ontogeny at specific stages. Metamorphic atrophy of oral structures occurs roughly in the reverse order of development, although the procedure is rapid and more haphazard than development.