oct.— dec. 1857.] The Pearl Oyster of Ceylon. 



95 



organ has been yet discovered. Doctor Johnson, in his valuable 

 work on Conchology, remarks on Conchiferce, " that every indivi- 

 dual is sufficient to its own felicity." But however correct this 

 may be, regarding the feeling of sexual gratification, it is clearly 

 established by M. Rudolph Wagner, that in some Acephalous bi- 

 valves, as likewise in Tu?iicata, Gasteropods and Polyps, the ova- 

 ries of some individuals contain a milk fluid, instead of ova ; and 

 that this milky fluid contains spermatozoa (seminal animalcules). 

 I have now to add the Pearl Oyster (Meleagrina Margaritifera) 

 as another of the bivalve species of Mollusc, which has individuals 

 with spermatozoa or seminal fluid, in organs similar to those which 

 in a larger number of individuals contain ova, or eggs. It will 

 not, perhaps, be necessary further to discuss this important sub- 

 ject, than to remark, that the Native diver's idea, that "there are 

 male and female Pearl Oysters ," is not altogether fabulous. The 

 important part which the male Oyster must play in the formation 

 of banks of Oysters, is self-evident, if it can be clearly established, 

 that the ova absolutely require the vivifying influence of a male 

 fluid. I have not seen more than three or four individuals with 

 this milky fluid, in 100 Oysters ; nor have I yet satisfactorily 

 made out any difference in the characters of the shells of the two 

 supposed sexes. The Native diver's opinion quoted by Captain 

 Steuart and Mr. Lebeck, viz., that "the large flat ones they call 

 males, and those that are thick concave, and vaulted, they call 

 females, " Peedoo Chippy," is not borne out by my microscopical 

 observations. I found well formed ova in Oysters which were 

 broad and flat. It is quite possible, however, that in the course 

 of this investigation, some external marks may be discovered, by 

 which the male Oyster can be distinguished from the female. From 

 the very small number of males (about 3 to 100) to females, I 

 can • easily fancy, that if by some natural or artificial cause, the 

 males are destroyed, the banks will not be enlarged ; and that 

 in time they will become extinct, i. e., supposing the majo- 

 rity of Naturalists are correct in their present view of the 

 Dioecious character of Oysters. It is just as likely, that Mr. 

 Garner's opinion will ultimately prevail ; viz., "that the or- 

 gans called ovaria, do at certain periods, secrete the seminal fluid, 



