CELL-DIVISION IN THE SEX CELLS OF TAENIA 207 
tions, but states that the mitoses are not at all frequent and 
that amitosis is the usual method of division. In his conclu- 
sions, in speaking of amitosis and mitosis, he says: ‘‘There can 
I think be little doubt that the two forms of cell division corre- 
spond to different physiological conditions of the nucleus. Judg- 
ing from the visible phenomena, it also seems probable that 
mitosis is associated with cyclical and amitosis with acyclical 
processes.’”’ And again he says: ‘‘The regions where mitoses are 
most abundant may be regions of slowest division instead of the 
only regions where division is occurring.”’ 
Hargitt (06) with reference to cell-division in Clava lepto- 
styla, says: ‘‘During the early cleavage, even up to the sixteen- 
cell stage, no evidence of mitosis has been found.’ Later in 
the same paper he says: ‘‘The facts seem clearly to justify the 
general conclusion that for a time in the early history of the 
development of the egg, nuclear activity differs greatly from 
the ordinary forms of mitosis, and appears to involve direct of 
amitotic division.” 
Beckwith (’09) in working on the same form, finds no evidence 
whatever of amitotic division, and states that both maturation 
and early cleavage take place by means of mitosis and not amitosis. 
She explains the nuclear nests of Hargitt by the condition of 
the nuclear reconstruction after cleavage and the lack of the 
appearance of the maturation divisions and fertilization by the 
fact that the eggs were not found at the right time of the day. 
Eggs collected from 4 to 6 a.m. show typical stages of maturation 
and fertilization. 
Richards (’09) finds no amitosis in the oogenesis of Taenia 
and concludes that his observations ‘‘on the process of oogenesis 
point to mitosis as the usual method of cell-division.”” The same 
author (Richards ’11) in his conclusions on his work on Moniezia, 
says: ‘In the early stages of sex cell development mitosis un- 
questionably occurs (probably periodically), while amitosis is not 
evident in my preparations; and finally there cannot be the 
slightest doubt that the cleavage of the ovum takes place by 
mitosis.”’ 
