NOTES ON SPOROZOA II. 
173 
individuals observed are iutra-cellular. In the blood of both 
tlie infected lizards the gre:it majority of the parasites occur 
under one of two different aspects, whicli might lead one, at 
first sight, to conclude that two distinct species were con- 
cerned ; but after a careful comparison of many individuals 
of both kinds, no doubt is left in my mind that they I’epresent 
respectively early young phases and rather later, older forms 
of one and the same parasite. The two types of form (as 
they may be designated for the present) are distinguished 
chiefly by the position and character of the nucleus, which I 
will consider in detail presently ; the latter feature can only 
be studied properly in preparations made by the “ wet ” 
method. I will merely say here that in the first type of 
individual the nucleus is situated more or less about the 
middle of the body (PI. 9, figs. 2-8, 19-29), whereas in the 
other type it is close to one end (figs. 9-18, 30-40). 
As regards their general appearance, both kinds of 
individual are usually bean-like in shape, the younger 
parasites being more slender and now and then slightly 
crescentic, the older ones broader and stouter. The indi- 
viduals of both types vary somewhat in size, the former being, 
as might be expected, slightly shorter on the whole and 
distinctly narrower than the latter ; but a few foi-ms which 
possess the nuclear characters of the first type are met with, 
which are approximately as large as others possessing a 
nuclear ari’angement of the second type. The dimensions of 
the younger forms, as seen on “wet ” films, vary from 8 g by 
2^ /i (6g. 22) to 9.^ g by 2| n (fig. 20) ; those of the older 
individuals from 9 g by 2^ p (fig. 39) up to 11^ /x by 3 ^ 
(fig. 33). On “dry ” smears the larger parasites are probably 
rather flattened out ; the extreme limits of variation in size 
(of either kind of individual) noticed are from 11 g by 2^ g 
(fig. 2) up to 13 ft by 41 fi (fig. 17). The largest bean-shaped 
individuals, however, such as those of figs. 14-17, have un- 
doubtedly acquired that appearance secondarily, by the 
lateral fusion of the two arms of a U-shaped form, the 
U-shaped form resulting in the first place from the further 
