THE PROTOZOA PARASITIC IN ARCHOTERMOPSIS WROUGHTONI 255 
unable to trace its origin and fate, but that it plays no part 
in division is shown by its absence in dividing nuclei. Probably 
it is cast out of the nucleus before division takes place. It 
appears to have no relation with the curious ‘ heterochromo- 
some ’ deseribed by Kofoid in T. campanula. 
DIVISION. 
As in Joenopsis polytricha the reproductive phases 
of P. pristina are difficult to find, and I have had to 
TEXT-FIG. 3. 
Early stage in the division of P. pristina; the centroblepharo- 
plast has separated into two, leaving a split in the protoplasm. 
From one of the centroblepharoplasts the threads still persist, 
but with their distal ends free from the nuclear membrane. 
1000) SHArs TIE. 
examine a large number of preparations to obtain those here 
described. Division is initiated by the splitting into two of 
the centroblepharoplast. This condition is rarely seen, partly 
because it is rare to find an animal so orientated as to render 
visible the split blepharoplast. Commonly it becomes inflected 
on to the body plasma, thus rendering it very difficult to obtain 
a clear picture. In the first stage of the process the two 
suspensory filaments become detached from the nuclear 
