THE OVUM IN THE AMPHIBIA. 

 chanically on the Spermatozoon or the Ovum in Impregnation. 



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abdomen. It does not return to the centre of the yelk, nor escape to the surface, 

 but is lost much nearer to the latter than to the former position ; and its disappear- 

 ance is the result of the endogenous development of cells in its interior. The egg is 

 cast loose into the abdomen, and then consists only of the yelk mass in its vitelline 

 membrane, and it is transferred to the mouth of the oviduct by the joint action of 



