P\ J. Meggitt 
51 
surface of the blastophore, give rise to a “morula” stage (Fig. 13). 
They then pursue one of two courses. They may remain attached by 
a narrow protoplasmic strand to the blastophore and grow considerably 
in size, or they may be entirely constricted off and lie freely in the 
cavity of the testis. In either case a considerable augmentation in size 
is observable. 
After a certain period of growth formation of spermatozoa begins. 
In this process the nucleus fragments, small pieces of chromidia become 
scattered throughout the cell and gradually diminish in size and number 
(Figs. 15 and 16). I have not been able actually to observe the forma¬ 
tion of a spermatozoon, the next stage seen being one in which the tail 
has already been partially formed and is attached at one end by a 
delicate fibre transversing the cytoplasm to one of the chromatin 
granules previously mentioned (Fig. 17). It seems possible that the 
tail is formed by the separation and differentiation of the portion of the 
cytoplasm between the chromidial fragment and the exterior of the 
cell. This stage, together with fully formed spermatozoa and still 
undifferentiated spermatids, is frequently found in the receptaculum 
seminis. The fully developed spermatozoon has a small distinct 
spherical head and a comparatively long tail curved and flexed 
(Fig. 18). 
The preceding account agrees as a whole with that given by Child (1) 
for Monezia, the chief difference being his omission of any statement 
regarding the presence and origin of the blastophore. In his account 
the cytophore usurps its function. There is also a difference in the 
behaviour of the spermatids. In Monezia they are apparently never 
separated from the cytophore but while attached form the spermatozoa ; 
in Cotugnia, on the other hand, they may lie freely in the cavity of the 
testis or even penetrate into the receptaculum seminis before producing 
spermatozoa: in any case their connection is much slighter than in 
Monezia. 
In general outline an agreement with von Linstow’s (4) account of 
spermatogenesis in Anomotaenia constricta Molin can be perceived. He 
certainly describes the spermatocytes (“Tochterzellen”) as being 
produced endogenously within the spermagonium (“Mutterzelle”), and 
asserts that all further processes occur within its limits, but the fusion 
of the spermatocytes to form cytophores (“Tochterzellen zweiter Gene¬ 
ration”), their division into “ Enkelzellen ” from which the spermatozoa 
are produced, and the formation of the spermatozoa themselves occur 
in almost identically the same manner as the corresponding processes 
4—2 
