Effect of luteinizing hormone on female Puntius ticto (Ham.).

Low doses (0.2 mg and 0.4 mg) of LH did not reveal any effect on the ovary of Puntius ticto (Ham.), but with 0.6 mg of LH the vitellogenesis began. Full maturation in the ovary was recorded with a total dose of 1.2 mg of LH and the fish spawned with a dose of 1.4 mg of LH.     

Changes in gill structure induced by BHC, lindane and endosulfan in the fresh-water teleost Puntius ticto (Ham.).

The effect of three organochlorinated pesticides on the gill structure of Puntius ticto, a freshwater teleost, was investigated. Fish exposed to sublethal concentrations of BHC (0.17 ppm), lindane (0.19 ppm) and endosulfan (0.20 ppm) were studied. The pesticides were detected qualitatively in the gill tissue by thin-layer chromatography (TLC). The results showed that they could be detected after 15 days' exposure, but not after 96 h exposure. Histopathological examination revealed several structural and functional changes in the gills. Exposure to BHC was followed by an inflammatory reaction and complete dystrophy of the lamellar structure of the gills. Lindane-treated fish showed disruption of the epithelial covering of the gills and excessive haemorrhage in the blood vessels. In exposure to endosulfan the gill lamellae shrank and became thinner.     

Melanophore characteristics in a fresh-water teleost, Puntius conchonius (Ham.)

The present study is an attempt to determine the factors responsible for the melanophore pattern of the freshwater teleost, Puntius conchonius (Ham.) under normal background conditions (i.e., the existence of a large round black spot on the middle of the side above the posterior part of the anal fin and the dull shade of the rest of the body which is brownish on the dorsal part, referred here in the present study as the general body surface and silvery along the lateral and ventral part of the body). On the basis of nature of their branching pattern various morphological types of melanophores are classified in a scale from the dark spot area as well as the general body surface. There are as many as 7 types of melanophores termed as A, B, C, AB/AC (all system I deep melanophores) and a, b and c (all system I superficial melanophores). The integument of the fish, however, possesses 3 kinds of chromatophores namely--melanophores, xanthophores and iridophores. The identity of the dark spot as clearly maintained entity independant from the general body surface may be attributed to greater number of system I melanophores, greater melanin content in the system I and system II melanophores, smaller interspaces between system I and system II deep melanophores, greater anastomosing in the superficial melanophores, larger size of system I deep as well as superficial melanophores. The reverse order of the above mentioned factors is responsible for the dull-brownish shade of the general body surface of the fish. The dark spot toward the tail end in the fish, possibly may serve to intimidate or misdirect attack and thus facilitate escape.     

Studies on the seasonal histocytological changes in the internal and chromaffin cells of male Puntius sophore (Ham) in relation to its reproductive cycle.

An attempt has been made to correlate the activities of interrenal and chromaffin cells with the reproductive cycle of Puntius sophore. Chromaffin cells do not have any significant bearing while interrenal cells undergo qualitative and quantitative changes which have been correlated with the various phases in the reproductive cycle of this fish. These cells undergo degranulation and vacuolisation during spawning phase, disorganisation during regression phase, and reorganisation and gradual growth during resting and prespawning phases. These cells thus appear to play an important role in the reproductive physiology of this fish.     

Seasonal studies on the adrenal homologue of female Puntius sophore (Ham.).

In female P. sophore the adrenal homologue is located inside its head kidneys and comprises interrenal cells and chromaffin cells. The clumps of interrenal cells surround the postcardinal vein and its major branches; they also lie in the haemopoietic tissue. The chromaffin cells mostly lie in the endothelium of the post-cardinal vein, while a few of them also lie interspersed among the interrenal cells. The seasonal study of the adrenal homologue shows that the interrenal cells undergo changes in bulk and composition in different months, while the chromaffin cells do not show any significant variation.     

Studies on the biology of some freshwater fishes Part VI. Mystus cavasius (Ham.)

Summary The biology of a freshwater fish, M. cavasius with particular reference to its length frequency, breeding and food has been described. length frequency distribution gave an indication of 4 modes during the quarter, July–September.Both the sexes attain maturity when they are approximately 10 cm long. Females grow larger than the males and are more abundant in the population. The spawning of this fish seems to take place during August and September. Maturing ovaries of females show only one batch of eggs which is probably shed in a single spawning act. The condition factor of the fish has no correlation either with the seasonal changes in maturity or with the feeding rhythm. The fish has an omnivorous habit and consumes all types of food available in the habitat. The feeding is high during the monsoon and winter months and low during the summer months.This work was carried out in the Department of Zoology, Aligarh Muslim University, Aligarh, U.P. India in continuation of the series I–III by Qasim & Qasim (1964) and IV–V published elsewhere by the present author (1970–71).     

Studies of the ultimobranchial gland of a teleost, Esomus danrica (Ham.)

The author describes the histophysiology of the ultimobranchial gland of E. danrica. The gland is the site of synthesis and storage of the polypeptide calcitonin, which has a hypocalcaemic effect. However, the sexual dimorphism of the ultimobranchial gland suggests that it also plays a role in reproduction, particularly in ovarian maturation.     

Histophysiology of the pituitary gland in correlation with the ovarian cycle in Tor (Barbus) tor (Ham.)

Summary The histophysiology of the pituitary gland has been studied in correlation with the phases of the ovarian cycle in Tor (Barbus) tor. The cyanophilic cells in the proximal pars distalis display changes related to stages in the maturation of the ovary. The cyanophils, which display hypertrophy and hyperplasia and undergo degranulation and vacuolation during maturation, prespawning, and spawning periods, are identified as gonadotrops. Apparently their glycoproteinaceous contents, gonadotropin(s), control the processes of vitellogenesis, ovarian maturation, and initiation of oviposition. Depletion of glycoproteinaceous contents in these cyanophils leads to atresia of oocytes at advanced stages, but it does not appear to interfere with oogonial proliferation. The neurosecretory materials are implicated in female reproduction.I am deeply indebted to Professor H. Swarup for suggesting and supervising this study and to Dr. Grace E. Pickford for her generosity in sending me xerox copies of some articles.     

Seasonal variations in the pharyngeal and pronephric thyroid tissues of the fresh water teleost Puntius sophore (Ham).

An attempt has been made to study pharyngeal and pronephric thyroid follicles and contribute seasonal changes in them in a fresh water teleost, Puntius sophore. Their activity has been assessed histologically by the study of size of thyroid follicles, the shape and cell height of epithelial cells and the nature of their colloid. These follicles exhibit notable seasonal changes and record two periods of activity, one in summer months from May to August and the other in November.