28 



On the upper or convex surface a number of very small 

 ones appeared : — 



Centimetres. 



■ 9 being between J 0'50 X 0'50. 



\and 0-40 x 0-40. 



1 of 0-80 x 075. 



1 of 95 x 0-80. 



1 of 0-90 x 0-75. 



1 of 1-50 x 1-90. 



1 of 2-10 x 2-10. 



1 of 2-10 x 2-60. 



15 



The concave surface bore in addition a large number of 

 barnacles (Balanus) and 21 serpulid tubes averaging from 1*75 

 to 2*00 centimetres in length ; on the convex side there were 

 but few barnacles but along the margin at one end was a 

 considerable quantity of short green conferva. 



The total oyster population on this tile was 8 individuals 

 above 2 centimetres in diameter and 15 under this size, the 

 dimensions of the tile, like those of all the others, being 9 

 inches by 6 inches approximately. 



The characteristics shown by these tiles put down on 30th 

 September were the presence of a small number of young oysters 

 of large size ranging from 1^ inch to 1| inch in diameter and a 

 larger number of small ones of half an inch in diameter and 

 under, but even these were not numerous. 



Lots 3, 4 and 5 laid down on the l%t\ 22nd and 29th 

 October. — These six bundles having their identity confounded 

 have to be treated as one lot. This however does not appear 

 to be of great consequence as they all appear equally thickly 

 covered with spat, so much so that the spat crowd one another 

 to such an extent as to cause contortion and an outturning of 

 the edges at right angles to the plane of the body. On this 

 account it is impossible to measure the length and depth accu- 

 rately, but an approximation of the average of the size which 

 predominates is 2-50 Y 2 - 70 centimetres. Taking two tiles 

 from different bundles, we counted 48 oysters on tile A, 

 varying between 2'70 X 2*70 centimetres and 2x2 centi- 

 metres, the majority inclining towards the larger size ; on tile 

 B the number of those ranging between these two sizes was 35. 

 In both cases there were a few of still smaller sizes, 17 in the 

 case of A, and 23 in the case of B ; these ranged down to '80 

 centimetre X '80 centimetre. On A there were one Anomia 

 2*20 centimetres in diameter, a few small barnacles, serpulid 



