the rains or with an exceptionally high tide, the creek becomes 

 continuous with the Sambasipalli kuppam creek to the south- 

 ward, giving a free run of water through the former. 



This Vannanturai oyster bed is much less extensive than 

 that in the Sinna Paraval ; in habit of growth, depth of water 

 over the bed, origin and constitution of the cultch forming the 

 foundation and surface of the bank or shoal on which the present 

 oysters are found, there are no differences to be noted. As in 

 the case of the first deposit described, the oysters on the higher 

 part of the bank are uncovered at low tide ; at this place the 

 oysters are found most crowded, becoming sparser as the water 

 deepens towards the middle of the creek. 



The upright habit of growth prevails again here in a most 

 marked degree and the muddy algal coating upon the valves, 

 the flat one more especially, is greatly developed. 



A considerable difference in average individual size from that 

 of the Sinna Paraval oysters was apparent to the eye, aud was 

 emphasized when exact measurements were taken. A large 

 proportion were 6^ inches and over in dorso-ventral length ; 

 a correspondingly large size in other dimensions was also found 

 as will be seen in the following table of the measurements of 

 twenty oysters taken indiscriminately from a heap : — 



Dimensions of 20 ousters from Vannanturai creek. ■ 



Number. 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



19 



20 



Depth 

 (Dorso- 

 Tentral). 



INCHES. 



/ 



4 

 4 



6* 



7 



H 

 5i 

 7| 

 7} 

 6* 

 6* 

 Gi 

 7 



6 | 

 6| 



6£ 



4| 



4 



Length. 



INCHES. 



Si 



If 



3 



3{r 



31 



2^ 



3 



3 



»i 



2f 



3 



•> 



4 



Thickness. 



INCHES 



u 

 11 



1:1 

 11 

 H 



H 

 i* 



if 



H 



1A 



li 



11 



li 



ii 



l* 



li 



4 

 li 



Average size . . 6-16 inches by 2'90 inches b) 1-32 

 inch. This average compares very well with that of the Sinna 

 Paraval oysters of 4'83 inches by 2-42 inches by T04 inch. 



