Showing papers in "Acta Zoologica in 1969"

Studies on the Diet, Feeding Mechanism and Alimentary Tract in Two Closely Related Teleosts, the Freshwater Cottus gobio L. and the Marine Parenophrys bubalis Euphrasen

Abstract: The diet and feeding mechanism in Cottus gobio and Parenophrys bubalis are described, together with the morphology and histology of the alimentary tract. Both species are sluggish bottom dwelling, carnivorous fish, and are capable of catching and swallowing relatively large prey. The gut is fully differentiated into esophagus, stomach, intestine with pyloric ceca, and rectum. The liver is morphologically separate from the pancreas, and separate bile and pancreatic ducts open into the base of one of the pyloric ceca. The organisation of the gut is well suited to the fishes' mode of life, showing adaptations for taking large meals which may be at irregular intervals.

The Epidermis of the Gopher Tortoise Testudo Polyphemus (Daudin)

Abstract: 1 Light microscopical histological and histochemical methods were used to examine the epidermis of the Gopher tortoise Testudo polyphenols. 2 The 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. 3 The 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. 4 Protein-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. 5 Growth 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. 6 The 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 Squamata.

Lymphomyeloid Tissues, Blood Cells and Plasma Proteins in Chimaera monstrosa (Pisces, Holocephali)

Abstract: 1). The hematocrit of Chimaera monstrosa is very low. Among the blood cells a large proportion are leukocytes. 2). The majority of the leukocytes may be regarded as lymphocytes or lymphocyte-like cells. Granulocytes constitute only a minor portion of the leukocytes of the blood but are abundant in the connective tissue. 3). From morphological grounds it is probable that lymphocytopoiesis takes place in the spleen, the cranial lymphomyeloid tissue, the thymus and possibly also in other less well defined lymphomyeloid structures. 4). An intense production of eosinophilic granulocytes occurs in the cranial lymphomyeloid tissue. 5). The plasma contains globulins but no albumin. Two or three fractions resembling immunoglobulins of higher vertebrates migrate towards the cathode. Age differences were observed. 6). The hypothesis is advanced that globulins originate from lymphocytes or lymphocyte-like cells of the blood and from blast cells of various lymphomyeloid tissues.

A Third Embryo of Myxine: Considerations on Hypophysial Ontogeny and Phylogeny

Abstract: A 4.5 cm Myxine embryo is described. The structure of its adenohypophysis suggests that it is derived from a dorsal thickening and proliferation of the nasopharyngcal duct epithelium as a homogeneous mass of cells. This process seems to start medially and proceed laterally. The characteristic lobulated appearance of the adult adenohypophysis is caused by a later invasion of connective tissue. Large areas of the ventral brain surface were found to be richly vascularized. No traces of an endostylar arrangement were observed and the thyroid follicles were distinct.

Le développement du télencéphale d'un poisson osseux primitif, Polypterus senegalus Cuvier

Abstract: Resume Les resultats de l'analyse du developpement embryonnaire du telencephale de Polypterus senegalus, ainsi que d'une courte description du telencephale de l'adulte ont ete compares aux donnees presentes dans la litterature scientifique, concernant le developpement et la structure du telencephale des Chondrosteens (Ch), des Holosteens (H) et des Teleosteens (T). Par l'organogenese et la morphologie de son telencephale, Polypterus presente de nombreux points de ressemblance avec les trois groupes ci-dessus cites. Dans la liste des resultats qui vont etre donnes, nous avons adopte le principe suivant: si le processus de developpement ou la structure dont il est fait mention concerne non seulement Polypterus, mais aussi les autres groupes de Poissons osseux, les initiales de ces groupes (Ch, H, T) seront ajoutees entre parentheses. 1 Comme chez tous les Gnathostomes, la morphogenese du telencephale du Polyptere commence par une inversion legere de ses parois laterales. 2 Par la suite, cette inversion, disparait. Les parois de l'ebauche telencephalique commencent a faire saillie dans la cavite ventriculaire et, correlativement, les taeniae (c'est-a-dire les deux lignes le long desquelles se rattache le toit telencephalique originellement etroit) se deplacent lateralement (H, T). 3 Ulterieurement, les taeniae se deplacent en direction ventrale, et l'apparition de sillons externes bilateraux (sulcus externus) indique les debuts du processus d'eversion (Ch, H, T). 4 Chez les Chondrosteens, les Holosteens et les Teleosteens, c'est l'epaississement des parois telencephalique qui domine pendant reversion; chez Polypterus au contraire, ces parois croissent bien plus suivant leur dimension dorsoventrale qu'en epaisseur. 5 Les bulbes olfactifs apparaissent au debut sous forme d'epaississements des parois telencephaliques. Plus tard, ils prennent la forme d'evaginations separees, possedant en propre leur cavites ventriculaires (Ch, H). 6 Outre reversion et l'evagination reelle bulbaire, une pseudoevagination (Kallen) se produit dans le telencephale de Polypterus. Ce processus conduit a la formation d'un septum ependymaire etendu (Ch, H). 7 Tot au cours du developpement, deux regions, qui sont respectivement l'area dorsalis telencephali ou pallium et l'area ventralis telencephali ou subpallium, peuvent etre distinguees d'apres des differences cytologiques (Ch, H, T). 8 La zone periventriculaire de l'area ventralis telencephali se differencie en un nucleus subpallialis dorsalis et un nucleus subpallialis ventralis (Ch, H, T). D'autres cellules de l'area ventralis migrent vers une position submeningee et forment un noyau subpallialis lateralis (H, T). 9 Une colonne de cellules migrantes dirigee rostroventralement, et provenant de la portion la plus dorsocaudale du manteau subpallie, aboutit a la formation du complexe des noyau entopedonculaires (Ch, H, T). 10 Dans l'area dorsalis telencephali du Polyptere, la couche du manteau embryonnaire persiste chez l'adulte sous forme d'une zone etroite de substance grise periventriculaire. Cette zone ne montre ni aux stades larvaires, ni chez l'adulte, de signe de differenciation en territoires distincts. 11 L'area dorsalis telencephali ou pallium du Polyptere montre un stade d'organisation bien plus simple que celui des Chondrosteens, des Holosteens et des Teleosteens. 12 Une couche cellulaire externe etendue se forme dans la partie rostrale evaginee du telencephale du Polyptere. Comme chez Acipenser, cette couche est en continuite avec la zone glomerulaire et appartient integralement a la formation bulbaire. Abstract In 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. 1 As in all Gnathostomes the morphogenesis of the forebrain of Polypterus commences with a slight inversion of its lateral walls. 2 During 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). 3 Later the taeniae are displaced ventrally, and the appearance of bilateral external grooves (sulci externi) marks the beginning of an eversion (Ch, H, T). 4 In 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. 5 The 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). 6 Apart from eversion and true evagination, an extensive pseudoevagination (Kallen) occurs in the forebrain of Polypterus. This process leads to the formation of an extensive ependymal septum (Ch, H). 7 Early 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). 8 The 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). 9 A 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). 10 In 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. 11 The area dorsalis telencephali or pallium of Polypterus is much more simply organized than that of the Chondrostei, Holostei and Teleostei. 12 In the rostral, evaginated part of the forebrain of Polypterus an extensive external cell layer is formed. As in Acipenser this layer is coextensive with the glomerular zone and belongs entirely to the bulbar formation.

Reproduction in the Indian Desert Gerbil Meriones hurrianae Jerdon

Abstract: In the present study the whole sample of 772 desert gerbils was collected from the semi-arid areas in and around Jaipur (Rajasthan, India). The male exhibits active spermatogenesis and well maintained accessory reproductive organs at any time of the year. Reproductive organs of the male gerbil are briefly described. The vaginal and urinary openings are independent in the gerbil. There are four pairs of mammae. Follicular development takes place cyclically. Maximum atresia of follicles is noticed during metoestrus. A well developed Graafian follicle measures 590 μ across its widest diameter. The average diameter of the ovum is 65 μ. At the time of ovulation formation of stigma occurs which gives way to the ovum. The corpus luteum is formed from the remaining granulosa cells of the ovulated follicle. Fully formed corpus luteum of the cycle (during dioestrus) measures 740 μ. Maximum development of the corpus luteum is seen during late pregnancy (22–25 days) when it measures 1250 μ. During pregnancy large Graafian follicles are absent. After parturition the ovary shows corpora lutea of lactation. Histological changes in the uterus and vagina during the oestrous cycle of the gerbil are described. There is less proestrus distension of the uterus as compared with the rat. During oestrus the uterine endometrium hypertrophies and there are some degenerative changes in the epithelial lining. The changes in the vaginal epithelium are clear cut and are correlated with the ovarian activity. During proestrus proliferation of the epithelium occurs and at ‘heat period’ or oestrus the epithelium shows formation of the stratum corneum and the shedding of cornified cells. In the dioestrus the vaginal epithelium is heavily infiltrated by leucocytes. There are three peaks in the incidence of pregnancy rate, i.e., February to April, July, and September to November. Pregnancy rate is lowest during summer (May and June) and winter (December and January). Average monthly litter size shows almost similar changes. The average length of gestation period is 30 days. There is post-partum heat in this animal. Formation of a vaginal plug is noticed following copulation. Litter size varies from 2–7. The average body weight of the new born young is 3.5 and 3.4 gm respectively for the male and the female. Weaning of the young is observed after about 20 days. Descent of the testes into the scrotal sacs occurs around day 28. Vagina opens after about 75 days.

Musculature of the Eyestalk in Crustacea

Abstract: 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.

Formation of the Corpora atretica in Notopterus notopterus (Pallas)

Abstract: 1 The 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 teleost Notopterus notopterus. 2 The 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. 3 Degeneration 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; and iii. 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 capillaries, later.

The Frog Tongue: I. General Development and Histogenesis of Filiform Papillae and Mucous Glands in Rana catesbeiana

Abstract: 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.

Effect of Insulin and Glucose on the Beta Cells of the Pancreatic Islets in Fresh Water Teleost, Ciarias batrachus

Abstract: 1 Ciarias batrachus is sensitive to mammalian insulin but becomes hypoglycemic after several hours of the treatment. The beta cells become degranulated and shrunken in appearance. 2 This 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.

The Frog Tongue: II. Histogenesis of Fungiform Papillae in Rana catesbeiana

Abstract: The histogenesis of fungiform papillae has been studied in two premetamorphic, ten metamorphic and one adult stage of Rana 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 comparing Rana catesbeiana with Rana sylvatica.

Hagfish Eye: Ultrastructure of Retinal Cells

Abstract: The retinal cells of the hagfish, Myxine glutinosa, possess at the ultra-structural level features which occur in the eyes of higher vertebrates. The “receptor” cells contain outer segment, ciliary structure and synaptic region. Other structures in the diminutive eye strongly suggest a functional state.

Distribution des néoblastes le long du corps de la planaire Dugesia tigrina et pouvoir de développement de différents morceaux isolés de celui‐ci

Abstract: Resume et conclusion Nous avons etudie les variations de la densite en neoblastes dans la region du corps anterieure au pharynx, dans la zone de division et dans la queue chez Dugesia tigrina, au cours du cycle de reproduction asexuee. La densite est beaucoup plus grande dans la queue que dans la zone de division et elle diminue encore dans la region ante-pharyngienne. Dans la region post-pharyngienne, la densite diminue de 36 heures apres la division jusqu'a la fin de la premiere semaine. Elle augmente legerement du 7e au 10e jour, c'est-a-dire peu de temps avant la division suivante. Dans la region ante-pharyngienne, la densite reste a peu pres constante pendant toute la duree du cycle de reproduction. Les variations du pouvoir de regeneration en fonction de l'origine des morceaux du corps et du temps ecoule apres la division ont ete suivies. Aucune relation nette n'a ete constatee entre le nombre des neoblastes et ce pouvoir. Par contre il semble etre dependant du degre de grandeur et de l'âge des neoblastes. Quelle est l'origine et quels sont les facteurs presidant au developpement des neoblastes restent les problemes essentiels et non resolus.

The Keratinised Teeth of Myxine glutinosa. A Histological, Histochemical, Ultrastructural and Experimental Study1

Abstract: 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.

Noradrenaline‐Containing Cells in the Epididymis and Vas Deferens of the Tortoise Testudo hermanni

Abstract: The vas deferens and epididymis of the tortoise, Testudo hermanni, contained very large amounts of noradrenaline but no certain amounts of adrenaline and dopamine. Small polymorf cells exhibiting a fluorescence typical of catecholamines were present in the tissues. It is concluded that most of the noradrenaline present in these organs is confined to the small cells. Their origin and possible function is discussed, and it is suggested that they may have the same function as the short adrenergic neurons present in the male genital tract of mammals.

On the Axillary Sclerites and Their Role in the Mechanism of Flexion and Extension of the Wings in the Indian Field Cricket Gryllus bimaculatus Deg. (Gryllidae, Orthoptera)

Abstract: A detailed account of the structure of the axillary sclerites of the fore and the hind wings is given. In the fore wing the first axillary is less developed than the second. In the hind wing the second axillary is less developed than the first. The inverse relative development of the first and the second axillary sclerites in the fore and the hind wings has arisen in response to the different type of role they have to play in the two wings. The structure of axillaries reveals that their modifications are intimately associated with the efficient mechanism of flexion and extension of the wings.

The Early Development of Pygoscelis adeliae (Adélie Penguin) up to the Formation of the Neural Tube

Abstract: The early embryonic development of Pygoscelis adeliae, up to the stage with fused neutral folds, was investigated by means of serial sections and compared with the development of the chick (Gallus domesticus). The total incubation time in the penguin is about 35 days, compared with about 20 days in the chick (Herbert 1967). This superior rate of development in the chick is likewise recognized in the early period of development; for fusion of neural folds is achieved 45–49 hours after laying in the chick and 6–7 1/2 days incubation in the penguin. Furthermore the time of origin and shape of the neural tube, notochord and heart show recognizable differences in the two genera.

The Frog Tongue: III. Histogenesis and Regeneration Following Complete and Partial Extirpations of Anlagen

Abstract: Tongue anlagen from which the anterior, posterior, right or left lateral halves had been extirpated generally regenerated completely within 15–30 days in Rana catesbeiana and R. clamitans. Regeneration was most rapid and greatest in posterior and median regions. Removal of anterior-posterior and left-right middle thirds and of anterior, posterior, right or left dorsal or ventral quarter anlagen (R. catesbeiana) showed similar regenerative gradients. Regeneration never occurred when entire anlagen were removed. Extirpations of early and half-developed lingual cornua were made in metamorphosing and young adult R. catesbeiana, R. clamitans R. palustris and R. pipiens. Regeneration occurred where preoperative cornua did not exceed 1.5 mm, but never when they exceeded this length. It is concluded that anuran tongue anlagen, at the stages operated on, possess considerable reorganizing powers following partial extirpations.

On the Morphogenesis of the Sound Producing Organs and the Skeleto‐Muscular Mechanism of Sound Production in the Indian Field Cricket Gryllus bimaculatus Deg. (Gryllidae, Orthoptera)

Abstract: The morphogeneesis of sound producing organs in Gryllus bimaculatus has been studied in detail. Though the auxiliary structure of the sound producing organs are fully formed in the last nymphal instars the essential structure of the sound production, namely the file, appears only at the imaginal moult. The teeth of the file show variation in number between 135–165. All the teeth have similar structures. The muscle 107a plays an important role in the sound production and is present only in the male.