The Spermatogenesis of Domestic Mammals, 



in. The Spermatogenesis cf the Mouse 

 and of the Rabbit. 



Kiyoshi Masui. 



(Fnm the Libjrdtory for Agcicultui-al Zoalogy, Director : Professor C. Ishiknw.i.) 



With Plates IV-X and one Text- I'ignre. 



Tlio L'livomosomes five now generally pro^'ed ta occm iu pairs b >tli in 

 germ cells as well as in somatic cells. In mammals, however, owing t j their 

 gi'eat number, it is very difEciilt t) detarmiue their relation accurately, and 

 the results of the investigations obtained by various workers, dift'er so 

 gi'eatly, that renewed studies are always io he welcomed, even iu one and 

 the same animals. 



It is for this reason, thai; the present investigation was undertaken, the 

 original object of which was chiefly the study of the chromosomes, but in 

 the coui-se of the investigation it was found uecessary to est?nd the researches 

 to thi cytoplasmic structures as well. The result was the jireseut paper 

 which deals with the entire spermatogenesis of the mouse and of the rabbit. 



Tlie author has preparetl the present parier under the dhection of 

 Professor Chiyomat.su Ishikawa to whom he wishes to express his hearty 

 thanks for the jpainstaking care and sympathy given him throughout the 

 ojurse of this study. 



Materials and Methods. 



The materials on which this study is based, consist of the testes of 

 piebald mice at different ages and those of young rabbit?. 



[Tour. Coll. Agrio., Vol. VIU. Xj. 2, 102!.] 



