138 



CEYLON PEARL OYSTER RETORT. 



In marked contrast to the poor growth seen on this bank was the rapid rate of 

 increase shown on transplantation to a locality under better conditions. Two of our 

 experiments may be cited to show tin's : 



(1.) A number of oysters collected on April 11th, 1002, from the Muttuvaratu 

 Paar, were suspended 5 days later in wire-net cages, at a depth (if 3| fathoms, from 

 the outrigger of a native boat moored in Galle Bay (see fig. 23). By May 9th a 

 marginal increase varying from 1*20 millim. to 1"50 millim. had been effected, and, 

 in addition, numbers of long finger-like processes had appeared, an evidence of very 

 vigorous growth due, no doubt, to the abundance of food with which the stomach 

 and intestine of specimens examined were found to be crammed. The internal parts 

 had undergone a corresponding increase, and the tissues from being thin and shrunken 

 had now become plump and healthy in appearance. We have the detailed measure- 

 ments of a number of transplanted individuals, from which we may select three as 

 samples : 



Specimen B, on April 13th, measured 58"50 X 54 - 50 millims., and by Mav 9th it 

 had reached GL60 X 56'70 millims., an increase of 3'10 millims. X 2'20 millims. 

 during 26 days, and not including the finger processes which had begun to form along 

 the margin. 



Specimen (omitting details), from April 1 5th to May 9th, showed an increase 



Fig. 45. Three transplanted pearl-oysters showing rapid growth. I. The dotted line shows the new 

 shell formed in 23 days. II. The dotted line shows the new shell formed in 21 days. 

 III. Oyster taken from Muttuvaratu to Cheval, showing a month's growth. All natural size. 



varying round the margin from 0'75 millim. to 3'80 millims. ; while if the fingers be 

 included, the growth during these 23 days was 9 "50 millims. (see fig. 45, I.). 



Specimen D was younger, 6 months old, brought from Chilaw Paar. From 

 April 15th to May 7th the increase was 1 "85 millim. on the average, not including 

 " fingers." The latter were present when put out at the buoy in Galle Bay. but a 



