The Spermatogenesis of Domestic Mammals. 
II. The Spermatogenesis of Cattle (Bos taurus). 
By 
Kiyoshi Masui. 
(From the Laboratory for Agriculturai Zoology. 
Director: Prof. C. IsHIKAwA.) 
With Plates XIV-XVI and one Text-Figure. 
The present paper deals with the -spermatogenesis of cattle which most 
probably is Bos taurus. Before going further it is perhaps advisable to 
state briefly the points of special interest revealed by this investigation which 
can be enumerated as follows :—1. In the testes of embryos and quite young 
animals amitotie division of spermatogonia frequently occurs. 2. One accessory 
chromosome is present which. is quite similar in its behavior and form to that 
of the horse.. 3. The behavior of the centrosome in the development of the 
spermatozoa differs considerably from that observed in the horse. 4. No 
evidence of the occurrence of parasynapsis as shown in the horse, is to be 
found, but accurate observation of the growth period brings us to the conclusion 
that telosynapsis probably occurs in the synaptic period of the cattle. 5. The 
chromosomes thus united by telosynapsis are separated in the first reduction 
division. 
The materials used in this study were chiefly obtained during the summer 
and autumn of 1917 at the slaughter house at Minowa in Tökyö. 
The testes which were removed from the scrotum were immediately 
cut into very small pieces and transferred into fixing agents. For 
the fixation FLEMMING’s chromo-aceto-osmie acidmixture (strong formula), 
Cuamrpy’s fluid Bourys picro-formol and Carnoy’s fluid (acetic alcohol 
[Jour. Coll. Agric., Vol. III. No. 6, 1919.] 
