Fig. 45. — Life-cycle of Hxmogregarina stepanowi Danilewsky. The 

 figures to the right of the dotted Une represent the phases 

 in the blood of the tortoise ; those to the left the phases in 

 the leech. A, sporozoite ; B, C, early schizogony producing 

 a large nuinber of merozoites ; D, merozoite penetrating a 

 blood-corpuscle ; E-H, later schizogony, in which few 

 merozoites are produced ; in i'^ is seen the recurved vermicule 

 within the corpuscle ; /, free merozoite about to enter 

 a corpuscle and repeat the stages D-H, or to initiate the next 

 phase ; J, K, final schizogonous generation which produces 

 the gametocytes ; L^, Lc^, sexually differentiated merozoites 

 which grow up into micro- (Mj) and macrogametocytes {M^) 

 respectively, and develop further in the leech when taken 

 up by it ; N, association of micro- and macrogametocytes 

 in the gut of the leech ; O, formation of four microgametes 

 by the microgametocyte ; P, one of the microgametes has 

 penetrated the body of the macrogamete and fused with its 

 nucleus ; Q, zygote with synkaryon, the degenerating 

 remains of the male gametocyte are attached to it, and are 

 also seen in the next four stages ; R, S, T, successive divisions 

 of the synkaryon ; U, ripe cyst containing eight sporozoites. 

 (From Minchin, after Reichenow.) 



