14 REPORT OF THE MALARIA EXPEDITION. 
The zygotes of the other two species contained fewer and much darker granules. In the 
youngest ones we considered we could distinguish between the melanin of H. malarice and 
that of H. prcecox ; the former possessing large and small granules of a dark brown colour, mixed 
together ; the latter possessing only large black granules. 
Our studies were not sufficiently exhaustive to enable us to speak regarding other differ- 
ences noted by the Italian observers. Nor had we time to examine cytological details — a 
thing to be regretted, because the Romanowsky method does not seem to have yet been correctly 
applied to the study of the nuclear changes in the zygotes. We easily noted, however, the 
structures first described in H. relkta ; namely, the alveolar, vacuolated appearance of the zygotes; 
the denser chromatoid granules ; the division of the parasites into 8 — 12 meres, giving rise to 
spherical blastophores carrying blasts in a manner recalling spermatogenesis ; and the minute 
spherical enlargements often attached to the immature blasts. We observed also that in the 
human species, as (to a less degree) in H. relkta^ zygotes which are little more than half grown, 
often contain apparently mature blasts. 
In several insects many full-sized zygotes appeared not to have ripened — that is, did not 
contain blasts ; although others containing blasts were found associated with them. 
