382 
Th e Sch izogi -egcivines 
(Fig. 4, D, ns). The latter gradually degenerates. We have then 
formed in each gametocyte a somatic portion and a sexual or gametic 
portion. The germinative nucleus itself next undergoes division into 
two, which Leger considers to be a “ reducing division.” Two small 
nuclei are thus formed, respectively styled the “ sexual nucleus ” and 
the “reduction nucleus” (Fig. 4, D, ng, nr). The sexual nucleus is a 
pronucleus, i.e. the nucleus of the gamete proper. We have illustrated 
here an interesting case of the maturation of the gametes, with 
reduction and degeneration of all except one from each gametocyte. 
Parthenogenesis, such as the origin of a sporocyst in each gametocyte 
of an associating pair, or the production of one sporocyst by one 
gametocyte the partner of which is sterile, is known to occur in 
Ophryocystis. Normally, copulation of two isogametes, as described 
in the foregoing section (p. 375), produces a single sporocyst. Inside 
the sporocyst eight sporozoites usually occur (Fig. 4, F, G). 
(2) Genus Eleutheroschizon. 
Eleutheroschizon duboseqi Brasil (1906) is a parasite of the gut of 
Scoloplos armiger Oerst (= Aricia muelleri Rathke) and was first 
described by Brasil. It occurs fixed to the epithelium or free in the 
lumen of the gut. The fixed individuals are about 30y long, and 
are dome- or bell-shaped. Their protoplasm is highly alveolar and 
their bases lie in hollows in the gut of the host. At the free extremity 
there is a cap with marked affinities for chromatin stains (Fig. 5, A, chr). 
The base is lobed, thus affording a superficial resemblance to Ophryocystis. 
The schizogony only is well known. The merozoites are claviform 
and about 2/a to 5/x long. They glide between the cilia of the gut 
epithelium, and then penetrate for about half their length into the 
cells. They are never completely intracellular. Each merozoite 
grows to about 8/a in length. The part of it containing the large, 
vesicular nucleus with its prominent karyosome is internal, the rest 
external. When the organism is about 10p, long, an apical point 
appears, into which the nucleus migrates. The parasite may merely 
continue to grow and remain uninucleate or it may develop into a 
schizont (Fig. 5, B). The schizogony is extracellular. 
When the parasite has attained the size of 15/a to 20/a, schizonts 
are formed, and nuclear division begins. A succession of such nuclear 
divisions occur, and the nuclei seem to be situated on bands of 
undulating protoplasm (Fig. 5, B). The nuclei finally reach the 
