188 
H. M. WOODCOCK. 
pcirasite, occiirring in L. mural is and probably also inL. 
agilis and viridis, for wliicb the specific name lacertas 
must be retained. Further, in my opinion, it is also prefer- 
able to retain Labbe’s distinct generic name Karyolysus 
tor this Ha3inogregarine, as also for any other similar form 
which may produce the same characteristic effects upon 
the host-cell ; I certainly consider such forms can be 
advantageously grouped together — if not in a separate 
genus, at any rate iu a distinct sub-genus — on account of 
their peculiar behaviour in this respect. It is only necessary 
to compare the effect on its host-cell produced by an ordinary 
lla; m ogregari n a to realise that there is a marked diffe- 
rence between the two types of parasite. Species of the 
genus llaemogregarina, whether from fishes or repitles, 
may often cause more or less hypertrophy of the red blood- 
corpuscle ; but they never stimulate, as it were, the cell- 
nucleus to undergo such profound changes as is the case with 
Karyolysus, where the nuclear alteration begins, as I 
have shown above, almost as soon as the parasite has invaded 
the corpuscle. I need only refer, by way of illustration, to 
the recent figures published by Minchiu and myself (loc. 
cit.) of H. triglm, by Neumann (23) of various piscine Haemo- 
gregarines, by lleichenow (loc. cit.) and also Hahn (8) of H. 
s t e pa n 0 V i , and lastly, the figures of many species from snakes 
given by Sambon and Seligmann (29)h In all these cases the 
host-cell nucleus is practically unaltered ; it may be now and 
then slightly flattened in appearance, but this is usually where 
it has been pushed to one side of the cell by the growing 
parasite, and is obviously due to a mechanical cause. It 
may be said, of course, that if a separate genus Karyolysus 
is to be thus recognised, the distinction between it and 
11 le m og r ega r i n a will be based mainly, if not entirely, on 
biological grounds. This is, no doubt, true; but one has not 
to look far for other iustances where a generic distinction, 
which is generally accepted, is recognised for biological 
' Suiue of these last should clearly be placed in the genus Karyo- 
lysus. 
