314 BIOLOGY. [Book iv. 



the nucleus or embryonary vesicle of the botanists is comparable 

 with the germlnative vesicle. We distinguish besides therein 

 a nucleole, which seems thoroughly to correspond to the germi- 

 native spot. The differences between the embryonary sac of 

 plants and the ovulum of animals bear only on the dimensions 

 or the number of the nuclei. The embryonary sac has in effect 

 dimensions relatively considerable, and it contains sometimes 

 two or three nuclei or embryonary cells. 



With regard to generation as with regard to all the grand 

 biological facts, we see evermore revealed the unity of life. We 

 shall have to signalise many other analogies in the pages which 

 have to follow and which are to be consecrated to a descrip- 

 tion of the principal phenomena of generation in the two 

 kinordoms. 



