UEPRODUCTIOX .(DF KALPIDORHYNCHUS AliENICOLiE. 571 
extrusion and the formation of the memhi’ane seem to take 
place simultaneously. 
After this the nucleus becomes approximately spherical, 
and its chromatin appears to be more finely divided and more 
closely packed than it was. The zygote at this stage often 
has a stalk-like projection at its narrow end, and this stalk 
persists so that the spore has the shape of a pear with a 
thickened stalk. Sometimes this stalk-like projection or 
elongation does not appear till later, but it is invariably 
present in the stage with four nuclei. The nucleus now 
divides into two, then into four, and ultimately into the eight 
nuclei of the sporozoites. It is my belief that at any rate the 
earlier of these divisions are mitotic, but I have not been 
able to prove this satisfactorily, and Mr. Cunningham is not 
of my opinion. It is at the stage with one spherical nucleus 
at the wide end of the cell that the cell-wall becomes 
thickened to form the sporocyst, and the zygote thus becomes 
a spore. Mr. Cunningham has mentioned the transparency 
of this sporocyst. I was able to see it, in preparations stained 
and mounted in spirit, as a dark line which follows the 
outline of the cytoplastn very closely. Karely, until the 
spores are fully ripe, i.e. until the cyto|)lasm is segregated 
round each of the sporozoite nuclei, does it leave the little 
stalk-like projection of the sporocyst (fia\ 8). 
In some of my preparations tlie ripe spores are burst. 
This may be due to reagents, the withdrawal of the cytoplasm 
from the stalk having left a spot vulnerable to pressure in 
the sporocyst. But it may be the natural course of events, 
for the sporocyst seems to fit the cytoplasm fairly tigditly, 
and the withdrawal of some of the cytoplasm from the stalk 
into the body of the spore may have caused the sporocyst 
to split. 
The sporozoites are vermiform, with pointed ends. The 
long nucleus occupies at least half the volume of each 
individual. The chromatin is finely divided and evenly 
distributed throughout the whole nucleus (tig. 8). 
It seems to me that it is only by following this chromatin 
