THE FROG: HISTOLOGY, GERM CELLS, DEATH 107 



these are now of the ordinary single kind. The second or 

 post-meiotic division follows the first without a resting stage. 



SPERMATOGENESIS 



Oogenesis 



/Gamerocyre 



Meioric 

 division 



Post meioric 

 division 



Germ cells 



etc. 

 Fig. 66. — A diagram of gametogenesis and fertilisation. 



It is an ordinary division, in which each chromosome splits 

 into two to give rise to one daughter chromosome in each 

 daughter nucleus, so that the daughter nuclei still have 

 each half the normal number. At fertilisation the zygote 



