392 K. MASUI: 
elongated, and a small portion of the cytoplasm finally comes in contact with 
the axial filament. 
In the mature spermatozoa a very small amount of cytoplasm is used to 
envelope only about half or a third of the length of the axial filament, the 
rest of the cytoplasm is probably cast off out of the spermatozoa (Figs. 95, 
STi Stok 
In the fimal development of spermatozoa a dense spherical eytoplasmie 
mass, similar in appearance to the idiozome, becomes frequently visible, which 
from the close similarity of its appearance and structure to that of the 
archoplasm, is probably to be regarded as a portion of the idiozome. This 
body is probably cast off out of the spermatozoa together with the cytoplasm. 
V. General Considerations. 
A. AMITOTIC DIVISION. 
Amitosis or direct division in the germ cell of the higher animals is in 
reality a rare and exceptional process. In the germ cells of amphibia it is 
described by LA VELLETE ST. GEORGE (’85), MEvEs (91), vom Raru (’91, ’93), 
BenpA (93) and McGrecor (’99); in insects by Preussur (’95), Gross (01) 
Foor and STROBELL (ll) and Wireman (’10). Carp (’07) found amitosis 
occurring in the germ cells of certain Cestoda and Annulata. 
As to the meaning of amitosis Mevezs (91, ’93) believed that in salamandra 
amitosis is a normal process in the spermatogenetic cycle and stated that the 
daughter cells (spermatogonia) produced by amitosis likewise come to divide 
mitotically, giving rise eventually to functional spermatozoa. On the other 
hand vom Rarx (91) asserted that in Astacus and other animals the cells 
divided by amitosis do not belong into the developmental cycle, but are 
destined to degenerate, and to be used as nutritive material by the normally 
developing sex cells. McGregor (99) in Amphiuma supported Mrves’s 
interpretation. CxtLp’s (’07) observation on the germ cells of Monizia is as 
follows: the early division of germ cells is amitotic, then comes a growth period 
at the beginning of which a spireme is formed, and subsequently they (the cells 
produced by amitotic division) divide mitotically during maturation divisions. 
In cattle, as stated above, an irregular outline of nuclei and a small 
