THE LIFE-HISTORY AND HABITS OF THE PEARL OYSTER. 



L39 



new set, enormously larger, were formed under the more favourable conditions, and 

 some of these were 10 millims. to II millims. long (fig. 45, II.). 



(2.) A number of the same pearl oysters were transplanted the following year, 

 during the fishery, from the Muttuvaratu Paar, on March 14th, 1903, to the Cheval 

 Paar, where they were kept under observation until April 19th. The great 

 improvement both in external size and internal appearance was especially interesting, 

 since we had an excellent control experiment in the similar oysters left on the 

 Muttuvaratu, which were examined on April 14th and found to be practically 

 unchanged. Those taken to the Cheval Paar had the margin thick and entire, with 

 no new growth and no fingers. After 3G days 4 of them showed the following 

 increase of size (one of these is shown in fig. 45, III.) : 



A added to margin 7 millims.. and fingers 9 millims. in length. 



B 



C 

 D 



(i 

 

 5 



K) 

 12A 



A very striking result, due in part possibly to suspension above the bottom ; but 

 the point is that the animal even when adult will re-act rapidly to improved 

 conditions. 



Some additional records from our lists of the average sizes of oysters from 

 different localities and of different ages may be of use. They may be conveniently 

 given in tabular form as follows : 



These, then, are young oysters in the beginning of their second year, and it will be 

 seen, comparing those of like age, that the North Modragam are larger than the 

 South-east Cheval, and the latter are larger than the North-west Cheval. 



Those given below are older oysters, mostly in their fourth year (see next page). 



T 2 



