10 MADRAS FISHERIES BULLETIN VOL. XI, 



In size it seldom exceeds 53 mm. in length by a thickness of 

 42 mm. 



It is noteworthy that this species is reported to be the subject of 

 very profitable cultivation in Japan, where from one culture area of 

 830 acres between 75,000 and 100,000 bushels are obtained annually. 

 The methods employed are simple; they depend for success upon 

 the fact that the fry of Area, after quitting the free-swimming 

 stage, tend to settle in definite areas in great quantities. Once these 

 are discovered the young ark-shells can be raked up in thousands — 

 usually when they are about 3 mm. long — and transplanted to 

 culture grounds where they are strewn and left to burrow into the 

 bottom. As they grow larger, from time to time they are redistri- 

 buted in order that overcrowding and food shortage may be avoided. 

 They are said to attain a marketable size in their third year. The 

 bulk of the produce is exported to China. 



OYSTERS (OSTREID^). 



Tamil— /!//■ (S'^'O, Pulicat; Pdtti {u/nluf-)^ Tuticorin. 



Malayalam — Miiriuga in Travancore and Cochin ; Muni in 

 Calicut. 



The edible oysters of Madras Presidency are two in number, the 

 backwater or mud oyster {Ostrea virginiaiia Gmelin) and the rock- 

 oyster {O. cucuUata Born). The former is the one specially 

 valued and the one which lends itself to cultivation ; the second, 

 whilst good flavoured, is rather tougher as well as smaller than 

 the other and is seldom eaten except at one or two places on the 

 Kanarese coast where it is specially abundant. 



The Madras backwater oyster is extremely variable in form and 

 has passed under many names. Among the more recent under 

 which it has been described is that of O. )fiadrnsensis by Preston ^ 

 It has however no outstanding differences from the common 

 American species and I agree with Vredenburg in believing 

 it to be in nowise separable from this widely distributed form. 

 It is appropriate to say here that very little is known at present 

 concerning the number and relationship of the different Ostreids of 

 Indian waters, and their nomenclature is in a state of considerable 

 confusion. A review of the species is urgently needed. To this 

 end I am accumulating material and I shall be very grateful for 



^ Preston, H. B.— Report on a collection of Mollusca from the Cochin and Enaur 

 backwaters. Records of the Indian Museum, Vol. XII, part i, Calcutta, 1916. 



