Volume 87, Issue 9
September 1978, pages 179-291
pp 179-194 September 1978
The amnion expands to accommodate the growing foetus without undergoing any noticeable histological change. The yolk sac is large and forms an extensive chorio-vitelline placenta on the lateral sides of the uterus during early stages of gestation. However, due to the extension of the exocoelom and the expansion of the amniotic cavity the vascular splanchnopleure of the yolk sac is separated from the placenta and is invaginated towards the abembryonic trilaminar omphalopleure. The endodermal cells of the yolk sac hypertrophy as the yolk-sac wall gets vascularized, and the mesodermal cells enlarge only during the final stages of pregnancy. The allantoic vesicle, which is large during early stages of gestation, becomes progressively reduced and is finally lost during the final stages of pregnancy. The placenta, which is extensive during early stages, becomes restricted to a discoidal structure on the mesometrial side of the uterus. The definitive placenta is labyrinthine and vasomonochorial. Numerous free chorionic villi, which come into direct contact with the decidua at the margin of the placental disc, constitutes an accessory syndesmochorial placenta.
pp 195-201 September 1978
Sexual maturity and breeding behaviour were studied in the freshwater crab,Barytelphusa guerini from April 1976 to March 1977. Animals attain sexual maturity at a carapace width of about 45 mm. The breeding period is from May to August with the peak activity during June and July. The post-reproductive and quiescent period is from September to December and the preparatory period for reproductivity extends from January to April. Adult animals with a carapace width of 45-60mm are reproductively more active while the activity declines in older animals. The animals show annual reproductive cycle and take part in reproduction twice during the life span, more so during the second year and less in the third year.
pp 203-209 September 1978
The histological scrutiny of the brain ofPoecilobdella viridis revealed two types (A and B) of neurosecretory cells, which are classifiedon the basis of size, shape and tinctorial characters. A cells are spheroid, rarely pyriform, with size (cell area) varying between 608 μ to 1701 μ. Their cytoplasmic granules take violet colouration with AF and deep red with Mallory’s triple stains. B cells are elongate or oblong with a size (cell area) ranging between 516 μto 831 μ. Their cytoplasmic granules are coloured blue to violet with AF and pink with Mallory’s triple stains. Neurosecretory material staining intensity of these cells is described light microscopically.
pp 211-216 September 1978
Five systemic organophosphorus insecticides were tested for their intrinsic toxicity in laboratory and persistence of their field-weathered deposits following spray onsarson crop (Brassica campestris L., var.sarson Prain) at recommended concentrations against mustard aphidHyadaphis erysimi (Kalt.). Phosphamidon and demeton-S-methyl proved to be sufficiently toxic compounds and provided protection to the crop for more than 3 days. Thiometon compared to dimethoate was a less toxic insecticide but relatively more persistent. Formothion was found to be the least toxic and least persistent insecticide.
pp 217-220 September 1978
Castor capsule borer,Dichocrocis punctiferalis Gn. is the most destructive pest of castor seed in India. Studies on the rate of multiplication were carried out at a constant temperature of 27±2°C under a limited space and sufficient food supply, the population increasedwith an infinitesimal rate (rm) of 0·0736, 0·0416, 0·0669, 0· 0492 and 0· 0864 and finite rate (λ) 1· 0763, 1· 0424, 1· 0691, 1· 0504 and 1· 0902 per female per day on maize, brinjal, bhindi, bottlegourd and pomegranate respectively. The net reproductive rate (Ro) was maximum (20· 19) on pomegranate. The popualtion on reaching a stable age distribution, in all the hosts, comprised approximately 97 per cent of the immature stages.
pp 221-228 September 1978
Bagrid catfishes of the genusMystus Scopoli are dominant in India and the East Indies and are rare in China. Eight nominal specieshave been reported as occurring in. China and referred to asMystus, Aoria orMacrones and their synonyms. Based on examination of type material it has been shown that with two exceptions all should be retained withinMystus. The two exceptions,Aorta cornula Chu (misprint forA. corsula (Hamilton)) is of doubtful occurrence in China andMacrones sinensis Bleeker belongs to the family Cranoglanididae.
pp 229-247 September 1978
Therea petiveriana (L.), the seven white spotted fessorial roach of the scrub jungles of South India is seasonal, univoltine and is very restricted in its distribution. The males emerge earlier than the females, soon after the first rain in summer. The cryptic nymphs are subterranean and the adults are predominantly crepuscular. The males that play the active role in courtship and mating, start the process by the characteristic antennal caressing. Depending on the intensity of receptivity of the relatively passive partner, he spares no time in backing into her genitalia to achieve the end to end position of genital connection. Mated couples go subterranean forthwith. The females choose reasonably wet substratum for resting as well as for ootheca deposition. The ootheca rotation is invariably dextral. Senescent females as well as virgins oviposit single eggs and the number of eggs in each completed ootheca ranges from 12–16. The process of oviposition starts early in the mornings as well as late in the evenings and the oothecae are carried longer when the substratutum remains dry.
The pairedpleural pouches are elaborate development of the pleuron of the second and third abdominal segments. These pouches are kept withdrawn into the body cavity by a set of retractor muscles that originates at the bottom of the pouch and gets inserted at the antecosta of the corresponding segment. Young adults, when perturbed, instantaneously lift the wings and fling open the tergites and sternites in order to expose the hairy pleats of the fully projected plural pouches. Projection is brought about by the haemocoelic fluid pressure. The well developed hypodermis of the pleural pouches of young adults has an outer tier of cuticle secreting small compactly packed cells and a basal tier of large secretory cells, the secretion of which is considered to function as alerting pheromone.
pp 249-255 September 1978
D. n. nasuta (2n=8) andD. n. albomicana (2n=6), the chromosomal races of thenasuta subgroup have mutual open genetic systems. Hybrid populations are completely fertile. By utilising fixed inversion differences in second and third chromosomes, the extent of coassociation of parental chromosomes in the gene pool of the hybrids have been estimated. There is a significant decline in the Inversion polymorphism of the second chromosome, while in the third chromosome both the parental and the hybrid associations are equally frequent. The reduction in the frequency of heterokaryotypes in the second chromosome is due to the establishment of different coadapted systems in the parental chromosomes which has been favoured by selection. This does not occur in the third chromosome. This dochotomy of differential coadaptation within the elements of the same genotype is the first of its kind and the implications of these findings are discussed.
pp 257-260 September 1978
Two new speciesLyssomanes karnatakaensis sp, nov. andL. bengalensls sp, nov. belonging to the family Lyssomanidae are described from India.
pp 261-266 September 1978
In animal experiments the Randomised Block Design is quite often used, the blocking based on some characteristics related to the character under study. Evaluation of the relative efficiency of the Randomised Block Design as compared to completely Randomized Design is necessary to decide whether a change of design is warranted. Data from 465 growth and/or protein efficiency ratio (PER) studies were processed to evaluate the relative efficiency of the randomised block design. The randomised block design turned out to be more efficient in growth and PER studies when blocking is based on age, sex and initial weight.
pp 267-278 September 1978
Twelve rhesus infants, reared in two groups in a forest habitat. Were observed for more than one year to study their reactions to conspecifics and the effect on home range size. The infants exhibited behaviours characteristic of wild rhesus monkeys in the absence of any prior physical exposure to their conspecifics. Both peer groups established intra- and intergroup dominance hierarchies. They remained aloof from wild rhesus monkeys and showed xenophobia to stranger infants. Their home ranges increased with age and rearing experience. No change was observed in home ranges after adding more individuals.
pp 279-283 September 1978
In the muscle ofClarias batrachus, variations in total nitrogen, protein nitrogen, non protein nitrogen, total water and water soluble nitrogen, total protein, pure protein, albumin, fat, moisture, ash, total inorganic and acid soluble phosphorus were found markedly influenced by the size of the fish. Excepting the ash which decreased upto 2nd size group, a substantial faIl in the relative concentration of these constituents was noted with the increasing length, the minimum being in 3rd size group. The fishes of larger size group (4th size group) contained slightly higher values. The fat value increased with the increasing size up to 2nd size group of fishes, whereas in the other size group, its value remained low. The moisture contents were found inversely related with the fat contents. The observed variations in different chemical constituents of fish with the increase in size appear to be related to the metabolic variations occurring during the growth and maturation cycle. In all size groups the electrophoretic patterns were more or less identical.
pp 285-291 September 1978
Lactating gerbils,Tatera indica indica (Hardwicke), retrieved their young, one by one, to the nests when the litters were displaced to positions away from it. The behaviour lasted for 22 days after parturition, but latencies for retrievals did not change with the growth of pups. However, the ‘grip’ used in retrieving varied with their age; pups were seized by teeth on the flank, by nape of the neck and skin on their back, in the order named. Models of pups presented to mothers were, however, ignored in another experiment.