EVIS HOWARD BERRY. 



of spermatogonial chromosomes. With this in view I selected 

 eight of the best polar metaphases of the last spermatogonial di- 

 vision, and drew them carefully with the camera. Seven of the 



d 



FIG. I. a-c, last spermatogonial division; <?, side-view of spindle; b, i', 

 metaphase groups, showing twenty- three chromosomes, odd chromosome (0) ; i/-t 

 growth period, showing characteristic forms of the odd chromosome (o) ; d, contrac- 

 tion phase, early growth period ; e, f, later stages showing the shortening and thick- 

 ening of the spireme threads; g, /i, late growth period, beginning of condensation ; 

 ?', prophase of first division. 



eight camera drawings gave a count of twenty-three chromo- 

 somes. In the eighth the chromosomes were so compact that I 

 could not count definitely beyond nineteen, but from the seven 



