NOTES ON SPOKOZOA— III. 
201 
chi'ornatin of the general nuclear substance is very much more 
prominent; i. e. in the form of numerous fairly large^ deeply 
staining grains, than is often the case in the corresponding 
phases of other parasites where a karyosome is present; and 
just the same condition is seen in the closely allied species, 
H. nicorim, accoi’ding to Miss Robertson’s description (loc. 
cit.). If the nuclear appearance of these parasites is com- 
pared with that, for instance, of the young phases of either 
K. lacertm, H. gracilis (Wenyon [36]), H. lutzi (Hart- 
mann and Chagas [10]), or of Barrouxia alpina (“Adelea 
ovata”) or Chagasia hartmanni, a striking difference 
is at once apparent; in the latter, most, sometimes nearly all, 
of the chromatin is contained, for the time being, in a distinct 
karyosome (or more than- one). It is especially in regard to 
this absence of a definite karyosome that the two species of 
Hmmogregarine from tortoises are interesting. Thus, Miss 
Robertson expressly states that “ at no stage does H . 
nicorim show in its nucleus the karyosome so characteristic 
'of Coccidia.” Now, in my opinion, H. stepanovi shows an 
important intermediate condition between the type of nucleus 
possessing a karyosome, as in the above examples, and a type 
like that of U. nicoria), where this organella is quite 
wanting. According to Reichenow, H. stepanovi has at 
certain periods of its life-cycle (which, in general, correspond 
to the phases when a karyosome is present in other forms) a 
definite rounded body, situated near the periphery of the 
nucleus, which is always very pule and faintly stained and 
appears quite different from the prominent chromatic 
grains. 
Reichenow uses the term 'Aiucleolus ” for this body, and 
this is most probably the correct name for this purticular 
structure, and indicates its true nature; but my reason for 
thinking so is not exactly the same as that given by 
Heichenow. It seems clear from the author’s description 
and figures that tlie body in question contains little or no 
cliroinatin ; it corresponds apparently to the true nucleolus 
of an ordinary tissue-cell, i . e . a body consisting simply of 
