Associated molluscs were the same as in the Sirma Paraval 

 bed ; barnacles were markedly extremely scarce. 



Stomach contents. — Diatoms appeared even more numer- 

 ous than in the sample already described, the number of 

 species being notably greater ; algal spores and broken filaments 

 were about the same in ratio, as also were sponge spicules. 

 Minute thread worms, noted also in the algal matting on 

 the valves, were particularly frequent, several being in the 

 field of the microscope at one time. One minute Daphnia- 

 like crustacean was noted. Sand grains and unrecognisable 

 debris as before. 



The bodies generally were far from plump, although some- 

 what larger, in consonance with the larger dimensions of the 

 shells, than those from the Sinna Paraval. The gonads also 

 were better filled, but still by no means fully developed, the 

 appearance being that at least a couple of months were yet 

 requisite to render them ripe for emission. 



To assess the probable age of these oysters is difficult. 

 We have already noted that owing to the great recession of 

 the water level during the dry season of 1905, the Sinna 

 Paraval oysters cannot be more than three years old, and yet 

 the present ones appear so very much larger as to suggest 

 greater age. If they are really older than the Sinna Paraval 

 ones, then the onlv conclusion to come to is that the water in 

 this creek was not reduced equally with that of the more 

 inland branches of the backwater. This is hardly possible, for 

 even if we grant that a great amount of water from the sea may 

 enter Karimanal inlet and this creek by percolation through 

 the closed bar during a dry season, the benefit of this supply will 

 be distributed throughout the whole extent of the lake unless 

 a bund be erected to separate the inlet and creek from the 

 remainder of the lake. The probabilities therefore are that 

 the majority of oysters on this bed did die off in 1905, that the 

 present oysters are of the same age as those in the rest of the 

 lake, and that their superiority in size is due to more rapid 

 growth induced by more varied and more abundant food- 

 supply consequent on their proximity to the rapid tide-flow 

 entering at the Karimanal bar. In Karimanal inlet, the sea 

 water is rich in minute organisms ; in the Sinna Paraval the 

 flow of water is sluggish and the plankton is often scanty. 

 In the latter case the oysters feed largely upon organisms bred 

 on their own valves and on the lake bottom adjacent ; in the 

 other the oysters besides having a similar supply have it 

 supplemented by the varied food brought by the passing tide. 

 It is a significant fact that the oysters of the Vannanturai 

 bed are all of the same generation. No younger generations 



