Volume 67, Issue 5
May 1968, pages 195-246
pp 195-200 May 1968
5-hydroxytryptamine produces an increase in the amplitude and frequency of the heart-beat ofPila. The threshold for the activity of 5-hydroxytryptamine is 10−8 gm./ml. However, this dose is not constant. In some cases it is 10−6 gm./ml. and in still other cases doses even upto 10−4 gm./ml. are ineffective. The action of 5-HT is not blocked by LSD. However, LSD 10−5 gm./ml. produces a positive inotropic and a very slight positive chronotropic response. The bromine derivative of LSD sometimes causes a rise in the threshold of 5-HT. Reserpine produces a positive inotropic and a negative chronotropic effect. The threshold dose for Reserpine is 10−5 gm./ml. The action of Reserpine is of long duration and both increase in amplitude and decrease in frequency go on for a long time in a progressive manner. The action of 5-HT and related compounds on the heart ofPila has been discussed in relation to that in other molluscs.
pp 201-206 May 1968
The present paper deals with the description of a new interstitial holothurian,Psammothuria ganapatii n. gen. n. sp., collected from intertidal sands on the Waltair coast. The form differs markedly in structure from the hitherto known species. Preliminary observations on the autecology of the species such as its adaptation to the biotic and climatic factors of the environment, method of locomotion, feeding, etc., are given.
pp 207-214 May 1968
Anabas testudineus (Bloch, 1792) andA. oligolepis Bleeker, 1855 are described, the latter being recorded for the first time from India. Juveniles and adults were collected from the market at Bhimavaram (W. G. District, Andhra Pradesh).A. testudineus can be distinguished fromA. oligolepis by: (a) less deep body; (b) longer pectorals; (c) shorter snout; (d) dark spot at base of caudal fading with age.
pp 215-223 May 1968
Investigations on breeding periodicities show that the marine crabCharybdis variegata is a biannual breeder. Males of the species have two peaks in their gonadial cycle. Increase in the gonad index coincides or just follows a drop in the hepatic index indicating probable utilization of reserved nutrients. Accumulation of nutrients as evidenced by a rise in the hepatic index precedes the second peak in gonad index. The nature of the breeding cycle of this species has been compared with those of other marine invertebrates with reference to geographical location and taxonomic relationship. The influence of environmental factors on the reproductive cycle ofCharybdis variegata has been discussed.
pp 224-229 May 1968
The presence of triphosphatase, diphosphatase and nucleotidase is reported in the scorpion muscle. Each phosphatase is shown to be substrate specific and to exist in three different ionic species with specific pH optima. With change in substrate from ATP to AMP, there is a gradual shift in the pH optima of the different fractions of the phosphatases towards the acid side. The possibility of differential intracellular localization of these ionic species of each phosphatase is suggested.
pp 230-232 May 1968
Batrachospermum vagum (Roth) Ag. is reported here for the first time from Gujarat. It was collected in the 2nd week of November 1967, from Lunawada, Panchmahal District, from a slow-moving stream, associated withCompsopogon sp. andLyngbya sp. The development of the sex-organs and cystocarps has been described in details.
pp 233-236 May 1968
A comparative study of the salinity tolerances of four common species of South Indian anurans shows that under natural conditions,Rana crassa, Rana hexadactyla, Ramanella variegata andBufo melanosticus may survive indefinitely in 25% n.s.w.Bufo melanosticus alone may survive in 35% n.s.w. indefinitely.
pp 237-246 May 1968