bluuebunny/crossref_metadata_2025 huggingface dataset:
A RAPID METHOD FOR SELECTIVE SILVER STAINING OF NERVE FIBRES AND NERVE ENDINGS IN MOUNTED PARAFFIN SECTIONS
Authors: Palmgren Axel
Published: April 2010

Abstract The staining described in this paper fundamentally is performed by two manipulations, namely (1) the treatment of deparaffinized sections for about fifteen minutes in a solution containing 15 per cent silver nitrate, 10 per cent potassium nitrate and 0.05 per cent glycine, and (2) the reduction for one minute in a solution of 1 per cent pyrogallol, 55 per cent ethyl alcohol and a trace (0.002 per cent) of nitric acid. After toning, dehydrating and mounting in the usual manner the sections generally are ready for examinations within less than an hour. The method is available for specimens fixed in the ordinary fixatives but those containing oxidizing metal compounds. The procedure is discussed from a theoretical point of view and some results are shown in photomicrographs.
The Frog Tongue: I. General Development and Histogenesis of Filiform Papillae and Mucous Glands in Rana catesbeiana
Authors: Hammerman David L.
Published: April 2010

The development of the tongue and the histogenesis of its filiform papillae and mucous glands have been studied in twelve premetamorphic, ten metamorphic and one adult stage of Rana catesbeiana.

The differentiation of the tongue anlage is described macroscopically and histologically. Its dorsal epithelium increases progressively in thickness. A maximum thickness of from then to twelve cell layers is reached just before the onset of metamorphosis. The general epithelium then undergoes degeneration between the developing papillae and mucous glands.

Four premetamorphic papillae are known to develop during the larval period. They form a transverse row across the approximate anterior‐posterior center of the tongue anlage. The growth and subsequent regression of these structures is described. A gustatory function is tentatively assigned to these structures.

Filiform papillae and mucous glands arise from either conical or rectangular cell groups in the dorsal epithelium of the tongue. The anlagen of these structures are first seen during larval involution at a stage usually just prior to the emergence of the forelimbs. The distal portion of two adjacent halves of an anlage migrate or grow towards each other and fuse to constitute a single papillary rudiment. The papillary core develops between these half anlagen. The epithelium of the papillae consists of but one layer of unciliated cells. Mucous glands differentiate from the basal portion of each cell group.

A general similarity in the development and histology of filiform papillae and mucous glands is noted when comparing R. catesbeiana with R. sylvatica. Certain developmental and histological differences do exist, however, between these two species.
The Keratinised Teeth of Myxine glutinosa. A Histological, Histochemical, Ultrastructural and Experimental Study1
Authors: Dawson Jennifer
Published: April 2010

The 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

The 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

In 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

The 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

Saccus 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.

Der 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

The 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

The 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

Le 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.

The 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

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

Siren 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

A 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

A 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

The 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

A 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

The 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

The 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.
Aminergic Innervation of the Cranial and Caudal Neurosecretory Systems in the Teleost Gillichthys mirabilis
Authors: Swanson Daniel D. , Nishioka Richard S. , Bern Howard A.
Published: April 2010

Abstract Numerous fluorescent varicosities surround most of the caudal neurosecretory neurons and also regularly occur among pars intermedia cells of the adenohypophysis in the teleost, Gillichthys mirabilis. The color of the varicosities, as well as their responses to pharmacological treatments, is diagnostic of catecholaminergic neurons and processes. No fluorescence characteristic of monamines is found in the rostral pars distalis, in the proximal pars distalis or in the cells of the nucleus lateralis tuberis (NLT), although fluorescent varicosities are found within the ventral hypothalamus in the vicinity of the NLT. Bilateral clusters of fluorescent cell bodies are located in the ventral hypothalamus (posterior to the NLT); some of these cells border the neurohypophysis. Fluorescent tracts from these cell clusters extend to a pair of elongate nuclei of nonfluorescent neurons which are surrounded by fluorescent varicosities. Alteration of osmotic conditions did not effect the fluorescence, except for the caudal neurosecretory cells of fish exposed to fresh water for long periods. Adrenergic nervous input thus seems to be an important component of both the cranial and caudal neurosecretory systems.
Ependymal Absorption of Peroxidase into the Third Ventricle of the Hagfish Eptatretus burgeri (Girard)
Authors: Nozaki Masumi , Fernholm Bo , Kobayashi Hideshi
Published: April 2010

Abstract The ependymal cells of both dorsal and ventral walls lining the lumen of the neurohypophysis of the hagfish, Eptatretus burgeri, absorb peroxidase injected into the third ventricle. Peroxidase diffuses rapidly into the connective tissue separating the neurohypophysis from the adenohypophysis, and also into the connective tissue located between the cell nests of the adenohypophysis.
Seasonal Changes in the Newt, Trituroides hongkongensis, Testis. I. A Histological and Histochemical Study
Authors: Tso E. C.‐F. , Lofts B.
Published: April 2010

The 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

Ultrastructure 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

In 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

Viviparus 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.
Light‐ and Electronmicroscopic Observations on the Blood Cells of the Atlantic Hagfish, Myxine glutinosa (L.)
Authors: Mattisson Artur G. M. , Fänge Ragnar
Published: April 2010

In the blood of Myxine glutinosa three cell lines may be distinguished: erythrocytes, granulocytes and agranulocytes. The erythrocytes are remarkably large, oval and nucleated. They are well defined in all their developmental stages by a characteristic micropinocytosis. They originate from blast cells which proliferate in the circulating blood. The blast cells probably form from agranulate stem cells of the intestinal myeloid tissue. The granulocytes constitute about half of the leucocytes. They are neutrophilic with a lobated nucleus. The granulocytopoiesis takes place in the intestinal myeloid tissue. The agranulocytes mainly include two cell types, termed spindle cells and lymphocyte‐like cells. These cell types, however, transform into each other. Macrophages occur essentially in the peritoneal cavity rarely in the blood. Transition forms between macrophages and granulocytes may exist. The blood also contains cells which on morphological grounds have been termed thrombocytes. Whether these cells are identical with those necessary for clotting of the blood remains to be proved. With the exception of erythroblasts, the different lines of blast cells are difficult to identify and distinguish from each other. Possibly all lines of blood cells originate from agranulate lymphocyte‐like stem cells, most of which are produced by the intestinal myeloid tissue.
Structure of Adnate Colony Portions in Crisiidae (Bryozoa Cyclostomata)
Authors: Silén Lars
Published: April 2010

The “rhizoidsrdquo; surrounding the base of the erect “colony” emanating from the ancestrula in the Crisiidae, especially the simple species Crisidia cornuta (L.), are a regular adnate system of autozooids. Each autozooid is composed of a proximal adnate part and a distal peristome (in some species kenozooids are possibly intercalated). The autozooid peristomes support erect branches identical in budding and structure with the branch emanating from the erect peristome of the ancestrula. Thus, the complete crisiid colony consists of an adnate system of ancestrula and autozooids, which form erect branches from their peristomes. The adnate zooid system is comparable in autozooid morphology and budding pattern with simple uniserial stomatoporids. The tentative hypothesis is proposed that the crisiid group has developed from primitive stomatoporids; the adnate zooid system of the stomatoporids apparently evolved peristomial budding to produce the erect colony branches characteristic of crisiids.
Functional Anatomy of the Olfactory Organ of Fish and the Ciliary Mechanism of Water Transport
Authors: Døving Kjell B. , Dubois‐Dauphin Michel , Holley André , Jourdan François
Published: April 2010

The olfactory organ of tench is functionally divided in a vestibule and a gallery. Experimental observations are presented indicating that an unidirectional watercurrent is created from the vestibule to the gallery via the corridors which are formed by the leaves of the olfactory rosette. The conditions for creating the watercurrents are: oriented and symmetrical beats of cilia situated on the walls of the corridors, and appropriate spacing of the corridors. This principle for water sampling is found in the olfactory organs of trout, carp, roach, catfish, eel, rockling and dogfish. In some other fishes studied the olfactory organs have accessory olfactory sacs and there is no subdivision in vestibule and gallery. In these organs the watercurrents are achieved by a pumping mechanism of the sacs.
The Epidermal Structures of the Tongue and the Buccal Cavity of the Brahminy Myna (Sturnus pagodarum Gmelin) and the Wagtail (Motacilla flava thunbergi Billberg)
Authors: Dubale M. S. , Thomas V. C.
Published: April 2010

A study of the epidermal structures of the buccal cavity and the tongue of two passerine birds, the brahminy myna (Sturnus pagodarum Gmelin) which feeds on insects, fruits etc. and the grey‐headed yellow wagtil (Motacilla flava thunbergi Billberg) which is solely an insectivorous bird was conducted with the help of light and scanning electron microscopes. The studies revealed the presence of spines and scales on the buccal roof and the tongue of both the birds. However, the brahminy myna carried spinelets over the spines and ultra fine hairy structures on the inner margins of the bifid region of the tongue. There were no spinelets over the spines of the wagtail but the surface was covered with numerous scales.
Feinstruktur der Knochenzellen in dem Gonopodium von Heterandria formosa Agassiz, 1853 (Teleostei, Poeciliidae)
Authors: Riehl Rüdiger
Published: April 2010

Osteocytes, osteoblasts and osteoclasts were recognized. The osteocytes lie in a thin zone inside of the basement membrane. The development of the rough endoplasmic reticulum indicates the presence of both active and inactive osteocytes. The spindle‐shaped osteoblasts synthesize the collagen fibrils of the preosseous matrix and are more frequent than the osteocytes. The elongated osteoclasts are rare.
Blood Cell Ultrastructure of the Ascidian Botryllus schlosseri L. II. Pigment Cells
Authors: Burighel Paolo , Milanesi Carla , Sabbadin Armando
Published: April 2010

Colonies of Botryllus schlosseri L., bred in the laboratory and genetically selected as regards the blue and/or reddish pigments, were used. The following phenotypes were investigated under the electron microscope: (a) blue colonies without reddish pigment; (b) reddish colonies without blue pigment; (c) colonies with both blue and reddish pigments; (d) colonies with neither blue nor reddish pigments. In the pigmented colonies, a specialized blood pigment cell type was recognized that, in giant membrane‐limited vacuoles, contained a great number of granules. In general, the granules were similar in size, not individually limited by a membrane and were made up with electrondense material often arranged in concentric rings. Although there could be some variability within the same cell, in each phenotype the granules displayed a characteristic pattern so that the differences in colour of the granules, as seen in vivo, were paralleled by differences in the ultrastructural architecture. In the unpigmented colonies also, granulated vacuolar cells, rare in number but morphologically comparable to the pigment cells, were seen.

On the basis of these results, the hypothesis of the existence of a prospective pigment cell and of a common origin for all the pigment cells of B. schlosseri is discussed.
An Ultrastructural and Fluorescence Histochemical Study of the Myenteric Plexus of the Stomach of the Rainbow TroutSalmo gairdneri
Authors: Santer Robert M. , Holmgren Susanne
Published: April 2010

The myenteric plexus of the rainbow troutSalmo gairdneriis enclosed within an incomplete Schwann‐like sheath which allows bundles of unmyelinated axons to pass into the adjacent smooth muscle layers. Neuronal and non‐neuronal constituents of the myenteric plexus are divided into smaller units by endoneurial collagen which in places condenses to form a perineurial covering. The myenteric plexus is avascular but arterioles and fenestrated capillaries are present close to the plexus in the intermuscular space. Small groups of neurones constitute the ganglia of the plexus but as yet few ultrastructural indications of differing neurone types have been observed. Within the neuropil of the ganglia five types of axon profile, characterised by their vesicle content, have been identified. One of these types was only recognisable following the administration of 5‐hydroxydopamine. Axo‐somatic and axo‐dendritic synaptic contacts were only made by Type 1 axons but these were uncommon. The presence of an adrenergic component of the myenteric plexus was confirmed ultrastructually following 6‐hydroxydopamine‐induced degeneration and also by Falck‐Hillarp fluorescence histochemistry which revealed an extensive distribution of adrenergic nerves in the plexus. The structural organisation of the plexus, the comparatively few ultrastructurally recognisable axon and neurone types and the sparsity of synaptic contacts all indicate that the teleost myenteric plexus is less complex than its mammalian counterpart.
Cerebral Neurosecretory Cells in the Millipede, Archispirostreptus syriacus, De Saussure (Diplopoda, Spirostreptiadae)
Authors: Warburg M. R. , Rosenberg Mira
Published: April 2010

The brain of the millipede, Archispirostreptus syriacus, was studied for its neurosecretory cells. Using standard cytochemical techniques, 2 types of neurosecretory cells could be identified. One of these cells could also be identified with the EM. In addition, three different cells were also observed in the EM and contained secretory granules of various sizes. Altogether, five neurosecretory cell types have been observed in the cerebral mass of this millipede.
Mechanisms of Defensive Stridulation in the Bushcricket Mygalopsis marki Bailey (Copiphorini, Tettigoniidae)
Authors: Bailey Winston J. , Sandow John D.
Published: April 2010

The copiphorine tettigoniid Mygalopsis marki uses two acoustic defensive displays which are quite distinct from the tegminal stridulatory mechanism. Both adults and nymphs utilise a stridulation produced within the head capsule. Observation and simple experiment reveal that this sound is produced in conjunction with the passage of air into the buccal cavity. There are large trachea beneath the frons which may be associated as amplifiers of these noises. The hind wings of the adults have small downward projecting spines set in open membranous areas of the wings. When the insect is excited, these spines engage a highly specialised area of the cuticle on the dorsal terga. The production of the noise requires only slight movement of the abdomen. Its role in defense is discussed.
Fine Structural Observations on the Turbellarians Stenostomum sp. and Microstomum lineare with Special Reference to the Extracellular Matrix and Connective Tissue Systems
Authors: Pedersen Knud Jørgen
Published: April 2010

Employing transmission electron microscopy, observations were made on epidermis, muscle cells and connective tissue systems, with special emphasis on extracellular matrix components (ECM), in two rather primitive turbellarians: Stenostomum sp. (Catenulida) and Microstomum lineare (Macrostomida). In Stenostomum the only ECM components found are basal laminae, predominantly situated subepidermally. In Microstomum ECM is well developed and connective tissue filaments abundant in conspicuous extracellular spaces. It is uncertain whether basal laminae exist. The finding of basal lamina structures as the only ECM component present in Stenostomum makes it now possible to establish a complete ECM and connective tissue hierarchy in turbellarians, ranging from a purely cellular type with no ECM present to systems dominated by ECM and very similar to loose connective tissue in vertebrates. Comparative aspects of ECM and connective tissue systems in turbellarians are discussed in addition to the difficulties and ambiguities regarding definition and nomenclature of basal matrices as basal laminae and subepidermal membranes.
Amoebocytes in the Lining of the Body Cavity and Mesenteries of Priapulus caudatus (Priapulida)
Authors: McLean Norman
Published: April 2010

Nuclei associated with membranes lining the body cavity in Priapulus caudatus are shown by electron microscopy to be the nuclei of amoebocytes. The membranes themselves are not cellular and do not constitute a peritoneum. Mesenteries, present in the body cavity, also are not cellular; amoebocytes occasionally are found within them. These findings weaken the idea that priapulids are coelomates, although unequivocal proof that priapulids are pseudocoelomates would require a fine structural study of the early developmental stages.
Fine Structure of The Paratympanic Organ in the Avian Middle Ear
Authors: Jørgensen J. Mørup
Published: April 2010

Light and electron microscopical examination of the paratympanic organ of 8 avian species reveals a sensory epithelium with hair cells and supporting cells, covered by a gelatinous cupula with numerous non‐crystalline deposits. The position of the organ is in agreement with previous suggestions of its function as an air pressure detector.
A Comparative Study of the Aminergic Structures in the Hypothalamus and the Hypophysis of Amphibian Larvae, with Special Reference to the Innervation of the Pars Distalis
Authors: Aronsson Stig
Published: April 2010

The distribution and occurrence of the aminergic structures of the hypothalamus and the hypophysis of the investigated species are very similar, except for the pars distalis. In the tadpoles of the anuran species Rana temporaria, R. arvalis, R. dalmatina, R. escutenta, Bufo bufo and B. calamita, the pars distalis is aminergically innervated (the Falck‐Hillarp technique), but these nerves disappear at the metamorphic climax. In the larvae of the urodelan species Triturus cristatus and T. vulgaris, the pars distalis is devoid of such nerves. Electron microscopical studies of R. temporaria, B. bufo and T. cristatus confirm these observations. A discussion of the functional significance of the pars distalis nerves and the phylogenetic role of the difference between anuran and urodelan species is given.
Secretin‐like Immunoreactivity in the Neural Complex of a Protochordate
Authors: Pestarino Mario
Published: April 2010

By means of immunocytochemical methods, a secretin‐like immunoreactivity is demonstrated in the neural complex of the ascidian Styela plicata. Secretinergic neurons are localized in the cortex of the cerebral ganglion and numerous secretin‐like immunoreactive cells are detected in some lobules of the neural gland. The possible functions of secretin‐like substances in the ascidian neural complex are discussed.
Anatomical and Histological Investigations on the Caudal Skeleton of Apteronotus leptorhynchus (Apteronotidae, Gymnotoidei)
Authors: Meunier François Jean , Kirschbaum Frank
Published: April 2010

The caudal skeleton of Apteronotus leptorhynchus was studied at various stages from hatching to the adult stage using anatomical and histological techniques. The caudal skeleton that supports the lepidotrichia is reduced to a rhomboid caudal plate (caudal cartilage) that extends the vertebral axis. This cartilage appears for the first time in 8 day old fish, postero‐ventral to the notochord. During its growth, perichondral and endochondral ossification occurs, beginning at the anterior end of the cartilage. Comparison with the anatomy and ontogeny of the typical caudal skeleton of teleosts allows us to interpret the caudal cartilage of A. leptorhynchus as an hypuro‐opisthural component that is homologous to the cartilage that occurs at the tip of the axial skeleton in Eigenmannia virescens.
Effect of 17 α‐Methyltestosterone on the Cytology of the Pituitary and the Liver, and on Plasma Electrolytes in Male Silver Eels
Authors: Olivereau Madeleine , Olivereau Jacqueline
Published: April 2010

Male silver eels kept in fresh water were injected with 17α‐methyltestosterone (MT). They received 5, 10, 15 or 20 injections (8 μg/g every other day) or 6 or 9 injections (4 μg/g or 2.5 μg/g once a week). Compared to solvent‐injected controls, the treated eels showed changes in the pituitary: prolactin, corticotropic, thyrotropic and melanotropic cells were stimulated. Gonadotropic cells had enlarged nuclei, but synthesis and storage of granules and large globules were not evident, despite the progressive testicular maturation. High doses of MT induced a liver hypertrophy, a drop in plasma osmolarity and sodium level. An increase in plasma calcium level is possibly involved in the reduced activity of PAS‐positive Ca‐sensitive cells of the pars intermedia. These responses, previously observed in estradiol (E2) treated eels, may suggest that MT is aromatized in the brain and/or the pituitary. However, the considerable stimulation of GTH cells which always occurs in E2‐treated eels is absent in MT‐treated eels. With lower doses of MT, changes in the pituitary and the testis were similar to those produced by high doses, although the Ca‐sensitive cells were more active. The decrease in plasma osmolarity and sodium level was less marked, plasma calcium was slightly reduced and the liver was not modified. There is no clear evidence in favour of E2 production. These data suggest that MT may stimulate the gonad directly, in agreement with biochemical data by Dufour et al. (1983).
Capillary Distribution in the Lateral Muscle of Axolotl (Ambystoma mexicanum Shaw)
Authors: Totland Geir K.
Published: April 2010

The vascular supply of red, intermediate and white fibres in the axial muscle of axolotl (Ambystoma mexicanum Shaw) was visualized with Indian ink‐injections and quantified with morphometrical methods on semithin sections.

Red fibres were surrounded by 1.4 ± 0.6 capillaries (mean + SD), the intermediate fibres by 1.2 ± 0.9 capillaries and white fibres by 0.3 ± 0.6 capillaries. The mean vascularized surface area per unit volume of fibre was 0.0159, and 0.0068 and 0.0007 (μm2/μm3) for red, intermediate and white fibres, respectively. A unit volume of mitochondria within each type of fibre was supplied by 0.15, 0.17 and 0.08 μm2 vascularized surface for red, intermediate and white fibres, respectively. This indicates that there exist a good balance between oxygen demand represented by mitochondrial content and oxygen supply represented by the vascularized surface.
Relations Between Hibernation and Ovarian Functions in a Temperate Zone Frog, Rana temporaria
Authors: Jørgensen C. Barker
Published: April 2010

Adult female frogs were exposed to artificial hibernation in a refrigerator, at about 1–3°C, 1–2 months earlier than in nature, isolated or together with males. Ovarian functional state at the beginning of hibernation was assessed from ovarian biopsies taken in mid‐September. All frogs ovulated during hibernation which was interrupted in mid‐May, but in seven out of 19 frogs ovulation was incomplete. The number of non‐ovulated oocytes varied from a minor fraction to about two thirds of the complement of vitellogenic oocytes, indicating that the follicle size reached at the time of induced hibernation was at the critical level for successful maturation. This critical size was about half the normal oocyte volume at the onset of natural hibernation. There was no vitellogenic growth during hibernation, which presumably constitutes the period of follicle maturation. In five of the frogs, oogenesis sensu stricto had occurred during the period of hibernation, some oogenic events being completely finished at autopsy in mid‐May and others still progressing.
Effect of Fat Body Excision in Female Bufo bufo on the Ipsilateral Ovary, with a Discussion of Fat Body‐Gonad Relationships
Authors: Jørgensen C. Barker
Published: April 2010

Complete removal of a fat body in female toads did not affect the oocyte populations of the ipsilateral ovary with intact blood circulation. It is argued that the inverse relationship in development typical of amphibian fat bodies and gonads does not reflect direct functional relations between the two organs, but may express shifts in anabolic patterns with the onset of sexual maturation.