31 



Growth in England and Holland is considerably slower, while 

 in America, whereas South Carolina oysters take 6 to 7 months 

 to reach a length of 2J inches, in the warm sounds of North 

 Carolina, they reach a length of 1| inch in from two to three 

 months.* In our experiment the rate of growth is considerably 

 better than any of these except perhaps that of North Carolina, 

 as we have seen that between 30th September and 12th 

 December or within 2 \ months they attain a length of 1^ inch, 

 while if we assume, as I think is fair, 22nd October as the 

 mean date for the fixation of the spat attached so closely to the 

 collectors laid out between 13th and 29th October, then these 

 oysters by the 12th December or in the space of If month, 

 reached a length of 1 T \ inch or 2 - 7 centimetres, a rate twice 

 and a half more rapid than that considered satisfactory in 

 France. 



11. Altogether the experiment is most satisfactory in its 

 results ; it has shown that the collection of spat can be carried 

 out by the simplest of meaus and at a very low cost ; it has 

 demonstrated conclusively the rapid rate at which growth pro- 

 gresses and confirms my conclusion arrived at by other reasoning 

 during my survey of Pulicat lake, that the Madras oyster will 

 attain an excellent marketable size within 2J years, possibly 

 even within two years. 



12. In conclusion it is interesting to note that the local 

 oyster of our backwaters, which I believe to be identical with 

 that of Ceylon backwaters, and which has been identified as 

 Ostrea cucullata, is more closely akin to the oyster of the east 

 coast of America, 0. virginica, than to the French and English 

 native. The appearance and form of the shell and the habit of 

 growth agree so closely with the characteristics of the American 

 species, that the two seem little more than geographical races 

 of one species, just as the pearl oyster of our coasts occupies 

 the same position towards the so-called species of the Gulf of 

 Mexico, the connection of the Gulf of Mexico with our own 

 seas being, indeed, much closer biologically than are the seas 

 of Europe. 



* Moore " Oysters and Oyster culture." U.S. Fish Commission Report for 1897, 

 Washington, 1897. 



Ennore, 

 2nd January 1909, 



