SUPPLEMENT. 1205 



the mobile small bodies destined to affect the fecundation 

 are seen emerging from them when the ovules, or small 

 eggs which they are to vivify, begin to make their appear- 

 ance. These molluscs are consequently hermaphrodite- 

 This is now an incontestible fact." 



Oysters may therefore be considered as being of one 

 sex, and producing eggs that are already alive, though until 

 quite lately this has been disputed. 



The most conclusive proof that fertilisation takes place 

 within the parent shell, and without contact with any other 

 agency, was that undertaken by the late Mr. Buckland. 



Some of the spat from a white-sick oyster was placed 

 in a test tube. It had been previously examined, and seen 

 to be in the immature shell-less state which the product of 

 white-sick oysters always shows under the microscope, and 

 it was kept at a temperature of 68 Fahrenheit for several 

 days. Gradually it passed through the yellow and slate- 

 coloured stages that spat is known to undergo, and it 

 ultimately became black. The darker it became, the more 

 fully was the young oyster developed, until at last the spat 

 appeared fully vivified, and exactly similar to that taken 

 from a black-sick oyster in fact a perfect animal. 



The holders of the theory that oysters are of two sexes 

 considered the black-sick oyster to be the male, and the 

 white-sick oyster the female. Now the former are always 

 found thoroughly vivified, the latter never. Then, as 

 impregnation must have taken place in some way, if the 

 dioecious theory is correct, it must the female which has 

 fecundated the male, a state of things totally opposed to 

 the general rule of nature. We have dwelt at some length 

 on this subject, as it is of the greatest importance that 

 oyster-culturists should understand the mode of reproduc- 

 tion. In artificial breeding there is always a large proper- 



