Development of the Mammal 289 

 MATURATION AND FERTILIZATION 



Of the processes of maturation and fertiliza- 

 tion in man nothing" is known by observation. 

 These processes have, however, been studied 

 in mice and, to some extent, in other mammals, 

 and, since they do not differ in their essential 

 features from the corresponding processes as 

 described in connection with the frog, we shall 

 simply refer to the earlier pages (10-17) of 

 this book. 



FlG. 87. OVUM OF BAT WITH FOUR SEG- 

 MENTATION SPHERES. (From Minot, after 

 Van Beneden and Julin.) 



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