On the Spermatogenesis of the Silk-Worm- (r) 
BY 
_ • 
KametarO Toyama, Assistant in the Zoological Institute , 
Agricultural College. 
With Plates III—IV. 
*. • 
The work which forms the subject of the following pages 
was carried on in the Zoological Institute of the Agricultural 
College during last year. My original intention was to determine 
the question, whether Verson’s large cell in the blind end of the 
testicular follicle is truly a genital cell or not, and in studying 
this I also touched upon the entire developmental history of 
the spermatozoa as well as the most interesting question in the 
development of genital cells, namely: the reduction of the 
chromosomes. 
Before going any further, I have, in the first place, to 
express my sincere gratitude to Prof. Ishikawa for his kind 
guidance and friendly counsel throughout the progress of my 
work in his laboratory. I am also very much indebted to Prof. 
Mitsuhuri of the Science College for his kindness in allowing me 
to use the library of the Science College, and also for various 
other matters. To Prof. Sasaki I am also much indebted for the 
materials. Thanks are also due to the director of the College, 
Prof. Matsui who allowed me to continue my work in the College 
after I passed through the university courses. 
Methods of Investigation. The entire process of the spermato¬ 
genesis was studied by means of sections and teased preparations, 
the former method affording more advantages than the latter for 
the researches of the division of the genital elements. 
For teasing the testicular follicles, I used acetic acid 
methylgreen for fixing and staining. As this causes the swell¬ 
ing of the chromosomes, it is very useful in calculating their 
number. 
The following fluids are used in hardening the sections : 
picro-acetic acid, sublimate alcohol, salt sublimate, chromo- 
(i) The ['preliminary note of this paper was published in the “Zoologischen 
Anzeiger” No. 438 this year. 
