218 C. CLIFFORD DOBELL. 
cyst belongs to Trichomonas or Trichomastix, so closely 
do they resemble one another (cf. figs. 28, 15). Only by 
seeing the living animals encyst can one make quite certain. 
Here, as in Trichomastix, there are no signs of any 
sexual process, either heterogamic or autogamic (see p. 
297). 
The account I have given of the life-history of the tricho- 
monads is so different from those of others that I must here 
say a few words regarding certain points. 
First as regards division. This has been said to occur by 
several observers, but details of the process are most meagre. 
For instance, Seligo (44) merely mentions the fact that he saw 
longitudinal division iu Trichomonas batrachorum. In 
Trichomonas lacerte Prowazek (78) believed that longi- 
tudinal division resembling that of Trichomastix lacerte 
took place, but he was unable to find all the stages and hisfigure 
is unconvincing. He further described a multiple division, 
which, from what I have seen in Trichomastix serpentis 
(56), I believe to have been really a degeneration pheno- 
menon. 
Kunstler (63) stated that Trichomonas intestinalis 
(from the guinea-pig) divided longitudinally, and remained 
active during the process. But he gave no accurate details. 
A description of the division of Trichomonasintestinalis 
from the mouse has recently been published by Wenyon (87). 
According to him, “there is a division of nucleus, blepharo- 
plast, and of the peculiar pointed organ which projects from 
the posterior end of the animal. The undulating membrane 
and its support with the flagelle (sic) appear to be new 
formations.” Later he states that the “ pointed organ ”’—i. e- 
the axostyle—“ divides by longitudinal division and is the last 
part of the animal to divide.” If Wenyon’s description be 
correct, then the trichomonads of the mouse divide in a manner 
which is totally different from that of the forms which I have 
investigated. It appears to me probable, however, that 
Wenyon is mistaken, and that the appearances he has seen and 
