Volume 22, Issue 6
December 1945, pages 331-397
pp 331-354 December 1945
pp 355-367 December 1945
There are two peaks of rainfall, the major one in July to August due to S.W. Monsoon and the minor one in October effected by N.E. Monsoon.
The surface temperature is high in April and low in August followed by a gradual increase up till November when again there is a slight fall.
The changes in specific gravity are parallel to the changes in surface temperature.
The maximum productivity of plankton takes place in the months of July, August and September followed by a rise in December due to the showers of the N.E. Monsoon and again a period of steady production.
The landings of fish are directly proportional to the quantity of plankton produced in the different months of the year. The fishery has invariably been found to be good after heavy rains when they bring plenty of ‘indispensable food substances’, thus enriching the “pasture of the sea” and increasing the food of fishes.
pp 368-373 December 1945
The structure of the nidamental glands ofG. tigrinus, M. nieuhofii,S. blochii andP. micrura is described.
Spermatozoa have been observed in the shell-secreting tubules of the nidamental giand ofG. tigrinus.
‘Tufts’ which are characteristic of the lamellæ of other nidamental glands, are absent in the ‘lamellæ’ of the shell-secreting region of the nidamental gland ofM. nieuhofii. No remnant of egg-case is seen in the uterus and it is suggested that owing to the absence of the ‘tufts’ and the simple structure of the ‘lamella’ probably no egg-case is formed in this species.
pp 374-377 December 1945
pp 378-397 December 1945