bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Keratinised Teeth of Myxine glutinosa. A Histological, Histochemical, Ultrastructural and Experimental Study1
Authors: Dawson Jennifer 
Published: April 2010

AbstractThe structure and function of the keratinised teeth of Myxine glutinosa have been studied. Following a detailed histological examination, histochemical, ultrastructural and experimental techniques have been used to study some aspects in more detail. A modification of the standard glutaraldehyde fixative for electron microscopy has been developed for Myxine tissues.The development of the horn cap (HC) and the pokal cell cone (PCC) have been traced. The HC is seen to increase in thickness with increasing length of the animal but there are irregularities in the development of the PCC which suggest that this cone may act as a replacement tooth for the HC. Experiments, in which the HCs were removed and the changes in the PCC observed, were performed to test this hypothesis. As a result of these and other observations it is suggested that it is possible for tooth replacement to occur.The structure and formation of the keratin in the HC and PCC cells has been followed using electron microscopy and histochemistry. The accumulation of keratin fibres in the early stages of PCC development has been traced, and keratinisation, which is probably associated with an increase in height of the cusps has been followed across a keratogenous zone at the bases of well developed HCs and PCCs.It has been established that the HC pigment granules are lipofuscin and that they can originate from lipid droplets.A detailed investigation has been made of the pokal cells. It is suggested that the beaded fibres, observed in electron micrographs of the apical band of these cells, are synthesised from lipid droplets in basal portions of the pokal cells, in a synthetic cycle, during which the nucleus descends through the length of the cell.
Musculature of the Eyestalk in Crustacea
Authors: Powar C. B. 
Published: April 2010

AbstractThe eyestalk musculature of Pandalus danae, Palaemon malcolmsonii, Penaeus indicus, Panulirus polyphagus, Astacus fluviatilis, Hippa asiatica, Diogenes miles, Paratelphusa guerini, Callinectes sapidus and Squilla harpax has been dealt with. The eyestalk consists of three segments, the proximal, the middle and the distal segments, in all the species. There is only one basal muscle, the anterior basal muscle, attached to the proximal segment of each eyestalk. The anterior and the posterior basal muscles can be grouped into three types, called the macrurous, the anomurous and the brachyurous types. The attractor muscles are intrinsic in the macrurous types, extrinsic in the brachyura and absent in the anomura. In the Reptantia the adductors are disposed along the long axis of the eyestalk while in the Natantia they lie across the axis.
The Development of the Osteocranium of the Egyptian Cobra
Authors: Kamal A. M. , Hammonda H. G. , Mokhtar F. M. 
Published: April 2010

AbstractIn the present paper, the otic capsule, palate, temporal bones, lower jaw and hyoid apparatus of the skull of the adult Egyption cobra, Naja haje, have been described in detail, and compared with those of the previously studied ophidian species. The otic capsule is composed of the prootic, laterosphenoid and opisthotic. The fenestra ovalis interrupts the suture separating the prootic and the opisthotic part of the otoccipital. The laterosphenoid is a rather minute bone lying lateral to the center of the prootic, with which it is completely fused both above and below without any trace of sutures.The palate is composed of the premaxillae, maxillae, prevomers, septomaxillae, palatines, pterygoids, ectopterygoids, basisphenoid and parasphenoid. There is no actual contact between the two prevomers. Each prevomer is composed of a median vertical part and a lateral horizontal one. It is quite separate from the premaxillae, maxilla and palatine. The septomaxilla is wedged between the nasal dorsally, the premaxilla anteroventrally, and the prevomer postero‐ventrally. The palatine is connected posteriorly with the pterygoid and laterally (by means of an outer process) with the palatal process of the maxilla. It carries about seven teeth. The pterygoid is a very long bone, it is connected with the quadrate only by a ligament. The pterygoid is free from the brain‐case, and carries about fourteen teeth. The ectopterygoid connects the maxilla with the pterygoid. The epipterygoid is completely absent. The basisphenoid is completely fused anteriorly with the parasphenoid without any trace of a suture. The parasphenoid is firmly fixed above to the lateral downgrowths of the frontals, and suturally articulates postero‐laterally with the lateral downgrowths of the parietals.There is only one temporal bone on either side which is regarded as the supratemporal. Thus the squamosal and tabular are completely absent. This supratemporal holds the quadrate to the cranium.Each mandibular ramus is composed of four distinct bones which are the dentary, splenial, angular and a composite bone. This composite bone is the result of the complete fusion of the articular, prearticular and supra‐angular. The coronoid bone is completely lacking.The cartilaginous hyoid apparatus is composed of two very long ceratohyals which are fused anteriorly to a small hyoid corpus.
A Theory Concerning the Early Evolution of the Visceral Arches
Authors: Jollie Malcolm 
Published: April 2010

AbstractThe visceral arches are usually assumed to develop in a similar way, from front to rear, with corresponding parts. The mandibular and hyoid arches do not follow such a pattern, rather some of the blastematic tissue of these arches became involved in the formation of the neurocranium as the trabecula and lateral commissure respectively. Thus this tissue was never developed as arch elements. Further, skeletal blastemas in the head are derived from delamination as well neural crest. The implications of these observations are explored.
Feinstruktur des Saccus dorsalis bei den Plötzen, Leuciscus rutilus
Authors: Obermüller‐Wilén Helena 
Published: April 2010

AbstractSaccus dorsalis in Leuciscus rutilus is a very folded area enclosing the epiphysis within its foldings. The dorsal sac consists of a single layer of cuboidal ependymal cells which have cilia and very irregularly shaped microvilli. The presence of vesicles in longitudinal rows indicate that these microvilli are very active. Bulbous outpocketenings from the apical surface contain glycogen. These bulgings may be pinched off into the lumen of the third ventricle forming rounded drops which contain richly glycogen. To increase the surface there are protrusions covered with microvilli. In the cytoplasm between the basis of those microvilli there are several coated vesicles which possibly sign micropinocytotic activity. Coated vesicles are also to be found in the lateral and basal parts of the cell, where they often have taken contact with the cell membrane. The ependymal cells rest upon a broad glycocalyx. In the subependymal connective tissue are wide capillaries with thinwalled fenestrated endothelial cells. The functional significance of these structures is discussed. A PAS‐reaction has been done. The ependymal cells and rounded drops in the ventricular lumen showed a positive reaction.ZusammenfassungDer Saccus dorsalis ist bei den Leuciscus rutilus ein stark gefaltetes Gebiet. Er umschliesst mit seinen Falten die Epiphyse, so dass diese im Dorsalsack versenkt liegt. Die Zellen bestehen aus einem einschichtigen kubischen Ependym. Diese sind mit Zilien und unregelmässigen Mikrovilli versehen, welche dadurch, dass sie Bläschen in langen Reihen enthalten, grosse Aktivität zeigen. Ausbuchtungen der apikalen Zellenoberfläche sind mit Glykogenkörnchen gefüllt. Diese Ausbuchtungen werden wahrscheinlich abgeschnürt und bilden dann runde, mit Glykogen gefüllte Tropfen im Ventrikellumen. Zellauswüchse, mit Mikrovilli bekleidet, vergrössern die Oberfläche. Akanthosome (coated vesicles), welche möglicherweise mikropinocytotisch aktiv sind, kommen reichlich zwischen den Basen der Mikrovillis vor, aber auch in den lateralen und basalen Teilen der Zelle, wo sie sich in Kontakt mit der Zellwand befinden. Die Zellen stehen auf einem breiten Glykokalyx. Im subependymalen Bindegewebe laufen Kapillare, deren Endothelzellen gewöhnlich mit Poren versehen sind. Die Funktionelle Bedeutung wird diskutiert. Eine PJS‐Reaktion wurde ausgeführt, bei welcher die Ependymzellen sowie runde Tropfen im Ventrikellumen positiv reagierten.
The Study of Prolactin in the Pituitary Gland of the Atlantic Eel (Anguilla anguilla) and the Atlantic Salmon (Salmo salar) by Immunofluorescence Technique
Authors: Aler Gudrun M. 
Published: April 2010

AbstractThe prolactin containing cells in the Atlantic eel and the Atlantic salmon have been localized by fluorescein‐labelled antibodies to ovine prolactin. Two fluorescence‐methods have been used: the direct and the indirect. Erythrosinophilic cells in the follicles of the rostral pars distalis were stained by the fluorescent antibodies in both eel and salmon. Eels from brackish water were transferred to fresh or salt water and differences in the contents of prolactin in the hypophyses were tested. Attempts were made at a semi‐quantitative estimation of prolactin, using a fluorescent antibody technique. Eels, which had been kept for three days in fresh water contained a smaller quantity of prolactin in their hypophyses, than the eels which were kept in salt water.
Caudal Musculature of the South Indian Flying Lizard Draco dussumieri Dum. and Bibr.
Authors: John K. O. 
Published: April 2010

AbstractThe modifications noticed in the caudal musculature of the South Indian Flying Lizard, Draco dussumieri, are described. The caudal musculature consists of the superficial ilio‐caudalis and ischio‐caudalis and the deeper ventral caudo‐femoralis brevis and caudo‐femoralis longus. There is an accessory tendon extending between the outer border of the tendon of the caudo‐femoralis longus and the tendinous origin of the gastrocnemius.In the male the copulatory organ is provided with a retractor muscle. Attached to the ventral surface of the penis sheath is another muscle which helps in everting the penis. This latter muscle is present in the female also as a vestigeal one attached to the postero‐lateral corners of the cloacal chamber.The modifications in the caudal musculature are attributable to the gliding habits of this lizard.Draco dussumieri, the South Indian Flying Lizard is unique in having a patagium for gliding from tree to tree. Associated with the development of the patagium, the musculature has undergone a number of adaptive modifications. The modifications of the trunk musculature have been published elsewhere (John 1970). The present communication is a study of the caudal musculature of this lizard.
Le rythme circadien dans la glande neurale de l'ascidie Ciona intestinalis. Etude d'anatomie microscopique*
Authors: Georges Danielle 
Published: April 2010

RésuméLe complexe neural de Ciona intestinalis a été fixé toutes les deux heures entre 2 h. et 24 h., puis examiné aux microscopes photonique et électronique. Au cours de cette période, la glande neurale subit des transformations qui la font passer d'un état épithélial (phase réticulée) à un état mésenchymateux (phase compacte), puis, après l'élimination d'une partie du matériel cellulaire disloqué et accumulé dans la région centrale, elle retrouve, par la périphérie, un état épithélial (phase réticulée périphérique). Ces transformations cycliques se produisent deux fois en 24 heures.Le passage des cellules d'une forme cubique à une forme étoilée a été décrit. Cependant la destinée des cellules libérées reste encore hypothétique et le problème d'une fonction exocrine ou d'une fonction endocrine de la glande est posé.La tunique fibreuse associée à la membrane entourant les lames glandulaires a été décrite et son rôle dans le transfert à la glande de granules de neurosécrétion en provenance des extrémités axoniques a été envisagé.AbstractThe neural complex of Ciona intestinalis has been fixed every two hours between 2 a.m. and 12 p.m. During this period, the neural gland undergoes morphological changes, turning from an epithelial structure (reticulate stage) to a mesenchymal structure (compact stage). After the elimination of part of the cellular material which had been disrupted and accumulated in the central area of the gland, it recovers an epithelial structure, starting from the periphery (peripheric reticulate stage). These cyclic changes occur twice in 24 hours.The ultrastructural changes that characterize the transformation from cubic to stellate shape of the glandular cells have been described. However the fate of the loose cells is still hypothetical and the question of the exocrine or endocrine function of the gland remains unanswered.The fibrous tunic associated with the membrane around the glandular laminae has been described and its possible role in the transfer of neurosecretory granules from the axonic endings to the neural gland is discussed.
Juxtaglomerular Cell Changes in the Euryhaline Freshwater Fish Tilapia mossambica During Adaptation to Sea Water
Authors: Krishnamurthy V. G. , Bern Howard A. 
Published: April 2010

Abstract

Following transfer to sea water, the juxtaglomerular cells of Tilapia mossambica increase in number and size, reaching a maximum at 12 days, and returning to the original condition by 30 days.
A possible role for renin in osmotic adaptation of teleost fish is suggested.
Lateral‐Line System of Siren intermedia Le Conte (Amphibia: Sirenidae), During Aquatic Activity and Aestivation
Authors: Reno Harley W. , Middleton H. Huson 
Published: April 2010

AbstractSiren intermedia is peculiar in that the lateral‐line system is retained throughout life, even though the animal is forced into terrestrial situations during aestivation. The lateral‐line system is constructed of neuromasts arranged in pit fields instead of pit lines as in most amphibians. The neuromasts are unusual, because the sense cells are arranged in a single row through the long axis of the organ and a few of the sustentacular cells contain “orange granules.”During aestivation, the neuromasts are either shielded by a secreted cocoon, or occluded by proliferated skin epithelium. Those organs occluded by epithelium undergo dedifferentiation which continues through postaestivation.Loss of the lateral‐line system by amphibians was apparently late in amphibian evolution. Gradual loss of the system suggests that retention and/or protection of the lateral‐line system proved maladaptive and physiologically too expensive. Thus the system was abandoned by most amphibian taxa at metamorphosis.
Neuroendocrine Phenomena in Aphroditid and Related Polychaetes
Authors: Golding D. W. 
Published: April 2010

AbstractA description is given of the neurosecretory system and a possible neuroendocrine system in polychaetes of the families Aphroditidae, Polynoidae and Sigalionidae. Two paired tracts and one unpaired tract of neurosecretory axons, and the ganglionic nuclei from which they arise, have been detected. The neurosecretory tracts are directed to the brain floor where they form a storage‐and‐release complex or neurosecretory neuropile, containing secretion‐laden fibre terminals which are diverse in character and can be distinguished on the basis of staining properties. Bundles of axons (transcapsular fibres) pass through the neurallamella and come into close association with the epithelioid cells of the infracerebral gland, a possible endocrine structure. The “gland” cells resemble monopolar neuron cell bodies in morphology and are of two types: a cells are devoid of secretory material, whereas b cells contain accumulations of PAF‐positive inclusions. Possible simple photoreceptors are associated with part of the cerebral neurosecretory system.
An Adhesive Function for Modified Cilia in an Interstitial Turbellarian*
Authors: Tyler Seth 
Published: April 2010

AbstractA modified cilium with an adhesive function has been found in an interstitial marine turbellarian Paratomella rubra (Acoela). This newly discovered cilium‐type is referred to as a haptocilium; it differs structurally from usual locomotory cilia only in the morphology of the tip. Inside the haptocilial tip is a lamellate, electron‐dense core, and visible outside the ciliary membrane of the tip is an amorphous secretion which is presumably the actual adhesive material by which the haptocilia are able to attach to surfaces. Haptocilia occupy a restricted area, a ventral tail plate, in Paratomella. They are motile and display a characteristic slow, irregular beat.
The Copulatory Organ of Pantodon buchholzi Peters (Teleostei)
Authors: Lastein U. , van Deurs B. 
Published: April 2010

AbstractThe copulatory organ of Pantodon buchholzi is described. It consists of two folded, complex structures, situated in two pouches, which open ventrally. The wall between the pouches contains the modified skeletal elements of a part of the anal fin. Laterally each pouch is covered by a bony plate. The structures are connected ventrally to the bony plates and consist of a spiral of parallel bone rays, connective tissue with many blood vessels, and covering epithelium. The organ is different from all other copulatory organs described in fishes.
Observations on Variations in the Male Sex Characters and Their Relation to the Androgenic Gland in the Shrimp Macrobrachium idae (Heller)
Authors: Thampy D.M. , John P.A. 
Published: April 2010

AbstractA majority of the males of the brackish water shrimp, Macrobrachium idae, show a hypertrophy in the length of the second cheliped, the length and spinuosity of the appendix masculina and the width of the vas deferens, during the breeding season. Statistical analyses of the measurements of these characters show that this hypertrophy has only very little correlation to the size of the individual, and that the above sex characters have marked variation in a population having the same body length. The hypertrophy of these structures is more linked with the extent of development of the androgenic gland. Also, in such individuals, the androgenic gland shows signs of increased secretory activity as evidenced by increase in size of the cells, vacuolisation of cytoplasm and presence of degenerative areas. It is suggested that there is a direct relation between the secretory activity of the androgenic gland and the hypertrophy of these structures i.e. there is a “cause and effect” relation between the androgenic gland and the primary and secondary sex characters.
Ontogeny of Double Cones in the Retina of Perch Fry (Perca fluviatilis, Teleostei)
Authors: Ahlbert Inga‐Britt 
Published: April 2010

AbstractThe formation of double cones in the retina of fry of Perca fluviatilis has been investigated by light and electron microscopy. The retina of newly hatched fry is provided with single cones and rods, single cones being the predominant receptor type. Double cones are seen for the first time 22 days after hatching. Mitoses are observed in the periphery of the retina, but are also seen in more central parts of the retina containing differentiated receptors and a cone mosaic. The fate of the cells resulting from the centrally located mitoses is not known. No signs of longitudinal fission of differentiated single cones are seen. It is suggested that double cones in the retina of perch fry arise by fusion of single cones which associate closely and develop subsurface cisterns coextensive with the region of intimate contact in the ellipsoid.During the first few weeks after hatching, there is a gradual shift in arrangement of the cones. In the newly hatched fry, the single cones are arranged in rows. When double cones are first seen, square‐pattern units appear, built up from four double cones and a single cone.
The Olfactory System in the Hagfish Myxine glutinosa
Authors: Theisen Birgit 
Published: April 2010

AbstractThe apical part of the olfactory epithelium in Myxine glutinosa was investigated by optical and electron microscopy. This part of the epithelium consists of supporting cells and two types of olfactory receptor cells, i.e., ciliated receptor cells and microvillous receptor cells. The olfactory cilia have a 9 + 0 pattern of the microtubules, occasionally with one pair of the doublets dislocated towards the center of the cilium. Giant cilia were observed. The supporting cells bear microvilli and are rich in tonofilaments. The supporting cells also have a secretory function, their secretion consisting mainly of acid mucopolysaccharides. An asymmetrical type of desmosome was found between the olfactory receptor cells and the supporting cells.
Seasonal Changes in the Newt, Trituroides hongkongensis, Testis. I. A Histological and Histochemical Study
Authors: Tso E. C.‐F. , Lofts B. 
Published: April 2010

AbstractThe testis of the newt, Trituroides hongkongensis is found to be made up of a chain of lobes each being divided into spermatogenetic zones which display seasonal cycles. Seasonal changes in the histology of the testis are studied. Lobule boundary cells are found present at the same time of the year when the secondary sex character, a lateral blue line along the tail, is best expressed. Both 5‐ene‐3β‐ and 17β‐HSD activities have been located in the lobule boundary cells which are suggested to be steroidogenic and their secretion may probably be responsible for the maintenance of the secondary sex character. The Sertoli cell, which originates from the follicle cell, shows accumulation of cholesterol‐positive lipid at certain stages of development but its capability in hormone production is uncertain.
Ultrastructure of the Ovary of the Hagfish Eptatretus stouti
Authors: Tsuneki Kazuhiko , Gorbman Aubrey 
Published: April 2010

AbstractUltrastructure of the ovary of the Pacific hagfish was studied. Attention was paid to the mesovarium, small oocytes, oocytes of intermediate size, large oocytes, postovulatory follicles shortly after ovulation, postovulatory follicles considerably after ovulation, and preovulatory atretic follicles. The progressive changes of thecal and granulosa layers in the course of egg development and degeneration are described. No cells showing the ultrastructural characteristics associated with steroidogenesis were found.
Size Relations of Lymphomyeloid Organs in Some Cartilaginous Fish
Authors: Fänge Ragnar 
Published: April 2010

AbstractIn elasmobranchs (sharks, rays) the total weight of lymphomyeloid structures isolated by dissection varied between about 0.6 and 1.0% of the body weight. In a holocephalan (Chimaera) the corresponding value was 1.7%. Reciprocal size relations may exist between different types of lymphomyeloid organs. A thymus was found in adult specimens of rays (Raja) and the rabbit‐fish (Chimaera). The lymphomyeloid organs supposedly are active in haemopoiesis and the immune responses.
Observations on the Gill of Viviparus bengalensis in Relation to Calcium Uptake and Storage
Authors: Gupta A. Sen 
Published: April 2010

AbstractViviparus bengalensis (Gastropoda: Prosobranchia) possesses a single bipinnate gill consisting of about 600 filaments. On account of large surface area, ciliation, polarized glycogen and alkaline phosphatase and an investing acid mucopolysaccharide layer, this organ is eminently suited to calcium ion uptake. In addition to this function, it is also secondarily an organ of calcium storage. This stored calcium is distinct from other forms of stored calcium already reported in that it is exceedingly susceptible to osmotic disturbances and very labile. It is possible that this serves as an almost instantaneously mobilizable reserve in times of calcium demand.