192 
H. ^r. WOODOOf'K. 
as a result of the valuable light thrown on the Avhole subject 
of the life-cycle of a Hca^tuogregariue by Keicheuow’s work ou 
H.stepauovi. Of course, this work has appeared since 
Fi-aiK’a’s papers were published, so that we have now a guide 
to the interpretation of the various phases which was then 
unavailable. As the general scheme of the life-cycle, so far 
as it is undergone in the Vertebrate host, has been shown by 
^liss Robertson (28) to be fundamentally similar in the case 
of another Haemogregarine also, I think we may regard it as 
probable that the life-cycle is similar, in its main trait.s, in 
other reptilian Hfemogregarines; and there is no need to con- 
sider that of Karyolysus as likely to be very different from 
that of Haemogregarina merely because of the biological 
differences between the two forms, i. e. with respect to the 
behaviour and reaction of the host-cells. Assuming a general 
agreement, a particular t 3 "pe or stage of parasite observed in 
a lizard might repre.sent anj’ of the following phases in the life- 
cycle of a single species: The young growing schizonts pro- 
duced from the sporozoites in a new infection ; the merozoites 
or growing schizonts resulting from a first type of schizogonj', 
e. g. with many merozoites (micromerozoites ?) ; the mero- 
zoites or young schizonts resulting from a second type of 
schizogony, e. g. with few merozoites (macromerozoites ?) ; 
lastly, the growing gametocydes, which may themselves be 
differentiated. As these various phases very likely show 
definite, though it may be slight distinctions from one another, 
if they were only observed casually-, as it were, and their further 
development was not followed, nor their connection with one 
another ascertained, some would at once jump to the erroneous 
conclusion that they constituted distinct and new species. 
Comsidering Fran^a’s three Karyolysus-forms separately, 
K. (U.) bicapsulata, which we may take first, is so named 
because of two caps of deeply staining matter which occur 
one at each end of the parasite. From Fran 9 a’s fig. 7 it is 
seen vei-y clearly, in the first place, that these “caps” are 
distinctly- outside the true envelope or capsule of the Haemo- 
gregariue, and secondly-, that they- resemble closely- in appear- 
