AND THE LOWER ANIMALS. 15 



CHAPTBE III. 



TRANSFORMATIONS OF THE EGG. 



F$om the almost exact resemblance presented by all 

 the ova which have been already examined, we may 

 conclude that the earlier phenomena of transformation 

 are the same. Such appears to me to be the general 

 result of the already numerous researches of hosts of 

 naturalists. It is true, that with regard to the higher 

 animals the harmony is far from being complete ; but 

 in very many of the instances the differences may be 

 explained on the supposition that each observer per- 

 ceived only certain phases of a complex phenomenon, 

 which he was ignorant of in its entirety. To under- 

 stand this entirety, we must have recourse to the 

 lower animals ; and even here we must select special 

 groups. An untransparent shell, the opacity of the 

 yolk, the length of time required for the alterations of 

 form and texture, are very frequently insurmountable 

 difficulties. It is because I found among annelids 

 and mollusks, animals having rapid transformations 

 and transparent eggs, that I have been able to dis- 

 tinguish the phenomena resulting from the vitality of 

 the germ itself from those induced by impregnation, 

 to determine the entire period of incubation, and to 

 prove the extraordinary fact of an egg-shell becoming 

 the skin of the future animal. Perhaps some of my 

 readers may recollect what takes place in Hermella 



