4 



In this connection it may be noted that the temperature of 

 water over this bed on 23rd August 1908 was 85° F., while the 

 specific gravity was 1,027-50. The temperature of the air in 

 the shade was 84° F. Time of day 5 p.m. 



The dimensions of six individuals taken at random were 

 as follows : — 



The average size of these may therefore be stated as 4| inches 

 by 2 T 5 2 inches by 1 ^ T inch. 



Dissection of a number of individuals showed the body or 

 soft parts to be of rather small bulk as compared with the 

 thickness and weight of the shell. The genital glands or gonads 

 shared in this weakness of tissue development, but how far this 

 may be due to seasonal causes we cannot say at present. Ripe 

 ova and spermatozoa, in separate individuals, were present in 

 the majority of cases but in small quantity ; the appearance 

 generally suggested that some considerable time must elapse 

 before full development would be complete. 



Examination under the microscope was made of the stomach 

 contents, and these were found to agree in constitution with 

 that of the algal felting coating the valves ; of recognizable 

 organisms, diatoms of several genera and species were by far 

 the most abundant with occasional algal spores, and a consi- 

 derable number of fragments of filamentous algce, chiefly green. 

 Sponge spicules, mostly slender rods with a slight knob at one 

 end, were also frequently seen. The remainder of the material 

 consisted of mud particles, vegetable debris, and a large 

 quantity of minute sand grains. 



Vannanturai Bed. 



This bed lies at the head of a long and wide horn-shaped 

 creek which passes westwards from the northern end of 

 Karimanal inlet past the village of Vannanturai. The present 

 bar entrance into Karimanal inlet is distant less than half a mile 

 from the creek mouth in a south-east direction ; the head of the 

 creek in the present water conditions of the lake ends close to 

 the village of Karimanal as marked on the district map. During 



