378 
The Schizogregarines 
trophozoites, which are at this stage gametocytes (Fig. 3, Yii), 
associate at the ends corresponding to their epimerites (Fig. 2, B). 
Each gametocyte rounds itself off, and a common cyst is formed around 
them (Fig. 3, vm). The nucleus of each gametocyte fragments and 
gamete nuclei are produced (Fig. 3, ix). Conjugation takes place be¬ 
tween pairs of gametes and sporoblasts are produced (Fig. 3, x ; also 
Fig. 2, C). 
The sporoblasts give rise to spherical sporocysts (Fig. 2, D; Fig. 3, 
xi, xn) which are 8/a to 10/a in diameter. The cyst of the sporocyst in 
S. echinatum is finely spined (Fig. 2, D). Each sporocyst contains four 
symmetrically arranged sporozoites (Fig. 2, E; Fig. 3, xu). The 
small number of sporozoites in the sporocyst is most unusual among 
Gregarines, and, as Caullery and Mesnil point out, recalls the Coccidia. 
The spherical shape of the sporocyst is also unusual. 
Y. General Life-History. 
The foregoing description and figures (Figs. 1, 3) will serve as 
outlines for the study of the Schizogregarine life-cycle, which I have 
set forth schematically in the following diagram. 
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