NOTES ON SPOEOZOA — III. 
213 
Discussing at the time the question of the Hajinogregarine 
nucleus, we considered this to be of a distinct type, entirely 
lacking a karyosome. Boruer (3), in his account of Eeptiliau 
Haetnogregariues (the best, as regards cytological details, 
which had been published up till then), had expressly stated 
that he never in any case found a karyo.'Ome present. 
IMoreover, mentioning the matter in conversation with Miss 
Robertson, she also agi’eed that the Hcemogregariiie upon 
which she was at the time working (H.nicoriae) also had no 
karyosome associated with its nucleus. The only mention 
in the literature up to then of the occurrence of a karyosome 
in the nucleus of a Haemogregarine was by AVenyon (36), in 
the case of certain phases of H. gracilis, from the liver of 
Mabuia. It appeared to us at that time highly probable 
that Wenyon had mistaken phases of some Coccidian parasite 
of the liver foi’ phases of the Htemogregarine, particularly as 
other, rather similar stages figured by Wenyon, which were 
undoubtedly referable to the life-cycle of H. gracilis, 
showed no karyosome in the nucleus. In the light of the 
observations discussed in the present paper, I willingly 
admit that our opinion was very probably mistaken, and 
that Wenyon may have been quite right in attributing all 
the phases he figured to the life-cycle of H. gracilis. 
In short, it is now jierfectly clear that the Htemogregariue 
nucleus cannot be considered as being of a distinct Dqie, but 
that, on the contra.ry, it shows close agreement with, or is 
easily derivable from, the Coccidian nucleus. Either a 
definite karyosome is present, at all events during some part 
of the earlier (schizogonic) phase of the life-history, when it 
behaves in a manner quite parallel to what is found in certain 
Coccidia, or else its complete absence is readily accounted 
for by a consideration of its behaviour as the development 
{>roceeds in those parasites in which it does occur. 
Therefore, in the case of II . t riglae, it is most probable 
that the conspicuous grains also represent karyosomatic 
elements, and that they do contain chromatin in some form or 
other. In our preparations we did not observe any division- 
