I2OO 



OYSTERS, AND ALL ABOUT THEM. 



I do not know the length of time of development, 

 from the beginning of segmentation of the egg until all 

 the embryos have passed out from the mother animal, but 

 it is probably less than four weeks ; for while, in the last 

 weeks of May in the years 1871 and 1874, from June 4 to 

 6 of the year 1873, and June 6 to 9 of the year 1876, in 

 hundreds of oysters which I opened, I found no embryos 

 in the beard, yet of 112 oysters dredged on the 1 6th of 

 June, 1873, five contained germs of a white colour, and 

 four contained germs already bluish, and possessed of 

 shells and vela. 



If by the end of the first week in June no eggs have 

 been laid, but by the beginning of the third week germs 

 are found of a bluish colour, then the transformation of 

 the white germ into blue cannot consume more than a 

 week, and these germs will hardly remain in the beard for 

 an additional period of more than two weeks. Those 

 oysters, then, which are found with eggs during each of 

 the following months, must be different individuals from 

 those which spawned during the earlier periods ; hence it 

 is right to add together the percentage of egg-bearers for 

 the entire summer. And since many oysters are found 



