2 PORTER. [Vou. XIV. 
A fair idea of the number and relative position of the cysts 
in the body cavity of the host can be obtained from PI. I, 
Fig. 1, which was drawn from a cross section of a greatly 
infested worm, and shows sections of eighteen gregarine cysts. 
Ordinarily the cysts appear white and opaque (PI. I, Fig. 2); 
mature specimens, however, when illuminated from beneath, are 
quite translucent and are seen to be filled with sporocysts. 
I have not been able to throw much light on the question, 
whether or not there is a conjugation or a division preceding 
the beginning of spore formation. However, the few cases 
observed which have any bearing on this question seem to 
point to a conjugation. In the only case of the unencysted 
condition found (Pl. I, Fig. 3), a division or conjugation — unfor- 
tunately one cannot say positively which — is in the act of taking 
place. This case alone cannot be taken as satisfactory evidence 
of either process; but in a dozen or more recently encysted 
gregarines I have noticed a constriction of the protoplasm 
which strongly suggests a conjugation, the evidence of which 
has not yet been fully obliterated (Pl. I, Fig. 4). I infer this 
because, apparently, in this form no division of the protoplasm 
precedes spore formation (Pl. I, Figs. 5,9, 10,12). It therefore 
seems probable that the case represented in PI. I, Fig. 3, is a 
conjugation preparatory to encystment. The close proximity 
of the two nuclei, which might at first sight be taken as evi- 
dence of recent division, is a condition which is entirely in 
harmony with the ordinary method of conjugation in monocystic 
eregarines, where, as is well known, the corresponding (ante- 
rior) ends of the copulating individuals are the ones to come in 
contact and fuse. 
It is to be inferred that the time intervening between encyst- 
ment and the formation of the first sporogonia is very short, 
because the number of cysts found either filled with sporocysts 
or in the process of spore formation is very large, the number 
of those in other conditions being comparatively small. 
Before the development of spores actually begins, however, 
the nucleus breaks up (PI. I, Fig. 6) and eventually disappears 
entirely (Pl. I, Fig. 7). During this process the character of 
the protoplasm changes from a loose vacuolated state to a more 
