136 GERM-CELL CYCLE IN ANIMALS 
Crstopa. Child concluded (1904) from a study 
of the cestode, Moniezia erpansa, that this method 
of cell division occurs in the antecedents of both 
the eggs and the spermatozoa. This writer has 
published a series of papers upon this subject using 
Moniezia expansa and Moniezia planissima for his 
material (1904, 1906, 1907, 1910, 1911), and his 
principal conclusion is that in these species the 
division of the cells destined to become eggs and 
spermatozoa is predominantly amitotic. Mitotic 
division also occurs but comparatively rarely. Cells 
which have divided amitotically then divide mitoti- 
cally during maturation and form typical ova. 
The nature of the nuclear division in the cestodes 
was later investigated by Richards (1909, 1911) who 
studied the female sex organs of the same species 
employed by Child as well as material obtained from 
Tenia serrata. Richards finds that mitosis unques- 
tionably occurs in the young germ cells but was 
unable to demonstrate amitosis. Richards claims 
that amitosis cannot be demonstrated except by the 
observation of the process in the living material and 
the subsequent study of this material by cytolog- 
ical methods. Child (1911) agrees with Richards 
that amitosis cannot be demonstrated in fixed 
material but nevertheless concludes after an examina- 
tion of Richards’ preparations “that direct division 
plays an important part in the developmental cycle 
of Moniezia, in the germ cells as well as in the soma” 
(Child, 1911, p. 295). 
Finally Harman (1913) was unable to find any 
