34 1 
as eleven sporoblasts packed together in an oocyst with a definite 
capsule. The individual sporozoites have no capsule. Their 
cytoplasm stains a light blue by Romanowsky's method. It is 
alveolar in structure and rarely contains granules of any sort, but 
may have occasional granules. The nucleus is placed centrally, is 
loose in texture and consists of a varying number of chromatin 
granules placed in a more lightly-staining matrix. From the analogy 
of other coccidia, we assume that the forms just described represent 
the completion of sporogony. The male and female gametes, which 
probably commence this cycle, and their conjugation have not been 
seen. Neither has the further development of the sporozoites been 
observed. 
The number of rounded merozoites (figs. 16, 17, 18), present in 
every part of the larvae and adults dissected, was often extraordinary. 
These organisms measured about 4 to 5/1 in diameter. They were 
either free or enclosed in a host cell. On becoming extracellular 
they were seen to possess a definite capsule (pink-staining); this was 
quickly discarded (figs. 1 8, 19) and the empty shells were very 
frequently seen. Often merozoites which had just cast their capsules 
occurred in groups of four (fig. 18). Four merozoites were, however, 
never seen within an unbroken capsule. As a rule whether intra or 
extra-corpuscular the merozoites occurred singly. When extra- 
corpuscular they were occasionally in pairs. Sometimes large intra- 
corpuscular cysts were seen which contained very large numbers of 
merozoites. The merozoites (figs. 16, 17, 18) consisted of a pinkish 
alveolar cytoplasm in which was situated a nucleus usually surrounded 
by an indefinite bluish area. In this bluish area a lighter, rounded 
spot was almost invariably present. A few chromatophilic granules 
and small clear spaces were frequently seen in the cytoplasm. The 
nucleus consisted of irregular masses of chromatin placed in a 
matrix. In some forms (fig. 16) the granules were placed at the 
Periphery of the nucleus and were joined by threads with a central 
darker-staining mass. In fresh specimens they were immobile. 
LITERATURE 
'• Ross. Parasites of Mosquitoes. Jour, of Hygiene, Vol. VI, No. 2, April 
' 9 °^. The subject is reviewed and discussed. 
