摘要:

Abstract1Light microscopical histological and histochemical methods were used to examine the epidermis of the Gopher tortoiseTestudo polyphenols.2The living germinative epidermis did not develop a granular layer and it was only a few cells in depth but the overlying stratum corneum was about twenty cells deep. The mature keratinized cells were extremely flattened and solid in structure but all nuclear basophilic staining was lost. The small horny scales in the neck skin were intermediate in appearance between the loose hinge horny layer and the larger compact scales of the legs. In the narrow hinge regions between the leg scales and also in the wider hinge zones in the neck epidermis, the stratum corneum was made up of layer upon layer of loosely arranged, separate keratinized lamellae. These were formed of horny cells joined at their lateral edges but free on their upper and lower surfaces.3The loose hinge horny layer contained some cystine but there was a much stronger reaction in the leg horny scales. Cysteine showed a reversed distribution with a greater concentration in the hinge horny layer and little in the leg scales.4Protein‐bound phospholipids were found in the epidermis and were also strongly present in the hinge horny layer and in the neck scales, but the compact leg scales showed only a very weak reaction. There was a similar distribution of protein‐bound calcium in the stratum corneum. Nucleic acids were not found in the keratinized cells.5Growth rings showed sites of retention in the stratum corneum of old horny cells of previous years. These occurred on the leg scales as well as on the carapace.6The stratum corneum of the tortoise appears similar in structure throughout its depth in contrast to the Squamata where differences occur through the thickness of the horny layer. These differences are discussed in relation to keratinization and sloughing. It is suggested that the tortoise horny layer is more homogeneous than in snakes and lizards because keratinization is probably a continuous process in contrast to the cycles of the Squam

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe 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 ofRana 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 comparingR. catesbeianawithR. sylvatica. Certain developmental and histological differences do exist, however, between these two specie

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe histogenesis of fungiform papillae has been studied in two premetamorphic, ten metamorphic and one adult stage ofRana catesbeiana.The gustatory papillae anlagen consist of club‐shaped groups of cells and are first seen just prior to the onset of metamorphosis. The distal portion of the cell group forms the end‐disc or taste bud of the papilla, while the proximal portion of the cell group forms the epithelial walls of the papilla's stalk region. The papillary core is derived from the general corium of the tongue.The end‐disc of a mature fungiform papilla possesses seven distinct forms of epithelial cells, viz.: goblet, rod, forked, fusiform, ciliated columnar, diagonal columnar and cuboidal cells. A nerve‐cushion is present beneath the end‐disc. It consists of a distal homogeneous zone and a basal fibrous portion. The papillary stalk consists of a single layer of unciliated cuboidal and diagonal columnar cells surrounding the papilla's core.Developmental and histological differences are noted when comparingRana catesbeianawithRana

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00528.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe structure and function of the keratinised teeth ofMyxine glutinosahave 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 forMyxinetissues.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.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00529.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Résumé et conclusionNous avons étudié les variations de la densité en néoblastes dans la région du corps antérieure au pharynx, dans la zone de division et dans la queue chez Dugesia tigrina, au cours du cycle de reproduction asexuée. La densité est beaucoup plus grande dans la queue que dans la zone de division et elle diminue encore dans la région anté‐pharyngienne.Dans la région post‐pharyngienne, la densité diminue de 36 heures après la division jusqu'à la fin de la première semaine. Elle augmente légèrement du 7e au 10e jour, c'est‐à‐dire peu de temps avant la division suivante.Dans la région anté‐pharyngienne, la densité reste à peu près constante pendant toute la durée du cycle de reproduction.Les variations du pouvoir de régénération en fonction de l'origine des morceaux du corps et du temps écoulé après la division ont été suivies.Aucune relation nette n'a été constatée entre le nombre des néoblastes et ce pouvoir. Par contre il semble être dépendant du degré de grandeur et de l'âge des néoblastes.Quelle est l'origine et quels sont les facteurs présidant au développement des néo

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Abstract1The formation of ‘preovulatory corpora atretica’ from the atretic oocytes and postovulatory corpora atretica from the ovulated follicles have been critically studied in the fresh water teleostNotopterus notopterus.2The oocytes which fail to mature or when mature ones fail to spawn, are degenerated and resorbed in the stroma of ovary and in doing so, the granulosa cells of their follicular wall, shown a varied activity of secreting the digestive ferments, enlarging in size, proliferation and phagocytosing upon the yolk and other cytoplasmic inclusions.3Degeneration and resorption of atretic oocytes have been studied in this fish by three different patterns:i. atresia in which the granulosa layer is hypertrophied and its cells proliferate;ii. atresia in which the granulosa cells do not proliferate but simply become enlarged, elongated and vacuolated; andiii. atresia in which cystic degeneration takes place.4‘Post‐ovulatory corpora atretica’ are formed from the evacuated follicles in which granulosa layer is hypertrophied and become proliferated. Its cells form a compact mass which is invaded by the blood cap

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Abstract1Ciarias batrachusis sensitive to mammalian insulin but becomes hypoglycemic after several hours of the treatment. The beta cells become degranulated and shrunken in appearance.2This species has a low glucose tolerance and becomes hyperglycemic by glucose injection. The beta cells show degranulation, vacuolisation and fusion probably due to hyperfunction but regain their usual form after 36 hours.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00532.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00533.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

RésuméLes résultats de l'analyse du développement embryonnaire du télencéphale dePolypterus senegalus, ainsi que d'une courte description du télencéphale de l'adulte ont été comparés aux données présentes dans la littérature scientifique, concernant le développement et la structure du télencéphale des Chondrostéens (Ch), des Holostéens (H) et des Téléostéens (T). Par l'organogenèse et la morphologie de son télencéphale,Polypterusprésente de nombreux points de ressemblance avec les trois groupes ci‐dessus cités. Dans la liste des résultats qui vont être donnés, nous avons adopté le principe suivant: si le processus de développement ou la structure dont il est fait mention concerne non seulementPolypterus, mais aussi les autres groupes de Poissons osseux, les initiales de ces groupes (Ch, H, T) seront ajoutées entre parenthèses.1Comme chez tous les Gnathostomes, la morphogenèse du télencéphale du Polyptère commence par une inversion légère de ses parois latérales.2Par la suite, cette inversion, disparaît. Les parois de l'ébauche télencéphalique commencent à faire saillie dans la cavité ventriculaire et, corrélativement, les taeniae (c'est‐à‐dire les deux lignes le long desquelles se rattache le toit télencéphalique originellement étroit) se déplacent latéralement (H, T).3Ultérieurement, les taeniae se déplacent en direction ventrale, et l'apparition de sillons externes bilatéraux (sulcus externus) indique les débuts du processus d'éversion (Ch, H, T).4Chez les Chondrostéens, les Holostéens et les Téléostéens, c'est l'épaississement des parois télencéphalique qui domine pendant réversion; chezPolypterusau contraire, ces parois croissent bien plus suivant leur dimension dorsoventrale qu'en épaisseur.5Les bulbes olfactifs apparaissent au début sous forme d'épaississements des parois télencéphaliques. Plus tard, ils prennent la forme d'évaginations séparées, possédant en propre leur cavités ventriculaires (Ch, H).6Outre réversion et l'évagination réelle bulbaire, une pseudoévagination (Kàllén) se produit dans le télencéphale dePolypterus. Ce processus conduit à la formation d'un septum épendymaire étendu (Ch, H).7Tôt au cours du développement, deux régions, qui sont respectivement l'area dorsalis telencephali ou pallium et l'area ventralis telencephali ou subpallium, peuvent être distinguées d'après des différences cytologiques (Ch, H, T).8La zone périventriculaire de l'area ventralis telencephali se différencie en un nucleus subpallialis dorsalis et un nucleus subpallialis ventralis (Ch, H, T). D'autres cellules de l'area ventralis migrent vers une position subméningée et forment un noyau subpallialis lateralis (H, T).9Une colonne de cellules migrantes dirigée rostroventralement, et provenant de la portion la plus dorsocaudale du manteau subpallié, aboutit à la formation du complexe des noyau entopédonculaires (Ch, H, T).10Dans l'area dorsalis telencephali du Polyptère, la couche du manteau embryonnaire persiste chez l'adulte sous forme d'une zone étroite de substance grise périventriculaire. Cette zone ne montre ni aux stades larvaires, ni chez l'adulte, de signe de différenciation en territoires distincts.11L'area dorsalis telencephali ou pallium du Polyptère montre un stade d'organisation bien plus simple que celui des Chondrostéens, des Holostéens et des Téléostéens.12Une couche cellulaire externe étendue se forme dans la partie rostrale évaginée du télencéphale du Polyptère. Comme chezAcipenser, cette couche est en continuité avec la zone glomérulaire et appartient intégralement à la formation bulbaire.AbstractIn this paper an analysis of the development of the forebrain of Polypterus senegalus, and a short description of the adult telencephalon of that species has been presented. The results of this study have been compared with data obtained from the literature on the development and structure of the forebrain of the Chondrostei (Ch), Holostei (H), and Teleostei (T). It appeared that, with regard to the embryology and morphology of its forebrain, Polypterus shows many points of resemblance to the three groups mentioned. In the subsequent survey of results these similarities have been indicated as follows: if the process or feature mentioned occurs not only in Polypterus, but also in the other bony fish groups, the initials of these groups (Ch, H, T) are added in brackets.1As in all Gnathostomes the morphogenesis of the forebrain of Polypterus commences with a slight inversion of its lateral walls.2During further development this inversion disappears. The walls of the telencephalic anlage begin to protrude into the ventricular cavity, and concomitantly the taeniae (i.e. the lines of attachment of the initially narrow telencephalic roof plate) move laterally (H, T).3Later the taeniae are displaced ventrally, and the appearance of bilateral external grooves (sulci externi) marks the beginning of an eversion (Ch, H, T).4In the Chondrostei, Holostei and Teleostei the thickening of the telencephalic walls continues during the eversion, but in Polypterus these walls increase much more in dorsoventral length than in thickness.5The bulbi olfactorii develop initially as thickenings of the telencephalic walls. In later stages they assume the configuration of separate evaginations, with ventricular cavities of their own (Ch, H).6Apart from eversion and true evagination, an extensive pseudoevagination (Källén) occurs in the forebrain of Polypterus. This process leads to the formation of an extensive ependymal septum (Ch, H).7Early in development two regions, i.e., the area dorsalis telencephali or pallium and the area ventralis telencephali or subpallium can be delimited on account of cytological differences (Ch, H, T).8The periventricular zone of the area ventralis telencephali differentiates into a nucleus subpallialis dorsalis and a nucleus subpallialis ventralis (Ch, H, T). Other cells within the area ventralis migrate to a submeningeal position and form a nucleus subpallialis lateralis (H, T).9A rostroventrally directed migration of cells, originating from the most dorsocaudal part of the subpallial mantle layer, leads to the formation of a complex of entopeduncular nuclei (Ch, H, T).10In the area dorsalis telencephali of Polypterus the embryonic mantle layer persists as a narrow zone of periventricular gray. Neither in the larvae nor in the adult does this zone show signs of a differentiation into separate fields.11The area dorsalis telencephali or pallium of Polypterus is much more simply organized than that of the Chondrostei, Holostei and Teleostei.12In the rostral, evaginated part of the forebrain of Polypterus an extensive external ce

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00534.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe eyestalk musculature ofPandalus danae, Palaemon malcolmsonii, Penaeus indicus, Panulirus polyphagus, Astacus fluviatilis, Hippa asiatica, Diogenes miles, Paratelphusa guerini, Callinectes sapidusandSquilla harpaxhas 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.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1969.tb00535.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY