ORIGINS OF AGAMIC PATTERNS 



605 



and decreasing dominance with physiological isolation progressing from 

 the posterior end anteriorly. The merozoites may develop either into new 

 schizonts or into gamonts which pair, encyst, and give rise to male and 

 female gametes by nuclear multiplication and the budding-off of cells 

 from a central mass. Two gametes unite, and nuclear multiplication and 

 cell formation about each nucleus give rise to sporozoites which become 

 schizonts (Fig. 187, A). 



Another schizogregarine, Caulleryella pipientis, has the form of Figure 

 188, A, in the nonreproductive stage but becomes spherical before repro- 



FiG. 188, A-C. — Schizogony of a schizogregarine, Caulleryella pipietttis. A, uninucleate 

 parasite; B, cell-budding about each nucleus; C, merozoites and cytoplasmic remainder (after 

 Buschkiel, 1922). 



ducing. Reproduction begins with nuclear multiplication; the nuclei ap- 

 proach the surface, mostly on one side of the spherical mass; and elon- 

 gated cell bodies bud out from the region about each nucleus, becoming 

 the merozoites and leaving behind a cytoplasmic remainder (Fig. 188, 

 A, B, C). Gametes also develop from the gamonts as cell buds about 

 nuclei, and sporozoite formation from zygotes is essentially similar to 

 merozoite formation (Buschkiel, 1922). If there is any appreciable domi- 

 nance in the uninucleate parasite, it is apparently lost before reproduction 

 begins; but position of nuclei at the stage of cell-budding (Fig. 188, B) 

 suggests a differential of some sort in the mass, perhaps persistence of 

 traces of the axiate pattern of the uninucleate form (Fig. 188, A). De- 

 velopment of merozoites (Fig. 188, B, C) also suggests relation to a polar 

 differential in the schizont from which they arise. 



