K. R. Lewin 
263 
From this wall of dense protoplasm is formed the radially striated 
layer described by Strickland. I see no reason for supposing it to 
consist of tubes radially arranged. 
The zygote remains uninucleate until it has embedded itself in 
a spore coat, within which the sporozoites are formed. In spite of 
repeated attempts, I have not been able to stain the contents of the 
maturing spores, and so can give no details of the nuclear divisions. 
The dehiscence of the cyst is described by Strickland. 
Fig. 7. 
Fig. 7. Cyst with zygotes (later stage). 
Fig. 8. Cyst with zygotes (later stage), 
residuum in centre. 
Zygotes and residuum mixed. 
Dense protoplasm at periphery, zygotes and 
Sexual Differentiation in A. bona. As has already been described, there 
is a small difference between the gametes formed by the two individuals 
associated in a cyst. As both sorts of gametes seem to be non-motile, 
it is idle to speculate as to which corresponds to the spermatozoon and 
which to the egg. 
There is also a difference between the sporonts, for in one series 
of sections, cut 6 /jl thick and stained rather deeply, a very distinct 
difference in staining capacity was noticed between the associated 
sporonts, recalling that found by Brasil (1905) and by Leger and 
Duboscq (1909). Unfortunately I cannot say whether the more deeply 
tinted individual was to give rise to the larger or to the smaller 
gametes. 
Taxonomy. 
There can be no question but that the gregarine under discussion 
represents a new genus. Strickland suggests a new family, the Agrip- 
pinidae, for its reception. To tliis Chatton takes.exception, being of 
the opinion that Agrippina should be included in the Actinocephalidae. 
If Chatton refers to the Actinocephalidae s. hit. of Leger and Dubosctp 
it is quite possible that he is right. There are, however, two difficulties, 
which further research may, it is true, dispose of; both sorts of gametes 
appear to be non-motile, and two sorts of male gametes have not been 
distinguished. 
