500 H. B. FANTHAM. 



in other Piroplasmata, by the primitive process of binary 

 fission (figs. 6 and 8). Each " raerozoite " or daughter 

 trophozoite formed from a dividing trophozoite ('' schizont ") 

 may, in turn, similarly divide. I am sorry that, in view of 

 the smallness of this iutra-corpuscular parasite, I am unable 

 to give cytological details of the process of binary fission 

 other than observing that the " chromatin body " of the 

 ellipsoidal trophozoite (schizont) divides into two parts, 

 arranged at the poles (fig. 5), and that the twin merozoites, 

 when longitudinally constricted apart (fig. C), remain 

 attached for a time by their pointed ends (fig. 8). How- 

 ever, in the case of erythrocytes enclosing several parasites 

 the numbers so enclosed are usually multiples of two (vide 

 figs. 10 and 13, but exception fig. 12). 



I have not yet seen examples of multiple fission forming 

 ''rosette" stages, as figured by Laveran (24), in the case of 

 P. equi, or "cross" stages of four, as mentioned by Koch 

 (21) in the case of P. parvum. 



Large extra-corpuscular, sausage-shaped ''gamete" forms 

 have been figured by Nuttall and Graham-Smith (41, PI. 9, 

 figs. 59 — 62) in the case of P. canis. Stephens and 

 Christophers (47, PI. 3, fig. 10), too, have figured a pair of 

 large intra-corpuscular forms, containing much chromatin, as 

 possible " gamete " forms of P. bo vis. In each case it is 

 only tentatively suggested that such are "gametes" (perhaps 

 more strictly " gametocytes "), but the correctness of these 

 and similar interpretations has not yet been established. 

 (Cf. Minchin [37, pp. 269-70] on Hunt's "crescents," 

 Ligniere's " gametocytes " and Dofiein's views, where he 

 remarks : — " The relations of the various phases hitherto 

 observed, and their true role in tlie life-cycle is, at present, 



so it might be considered unnecessary to use the term "schizogony" for 

 simple binary fission, or "schizont" for a trophozoite so dividing, as the 

 tropiiozoite is not here sporulating into many daughter forms, but usually 

 into two only, which themselves, perhaps, need not be specially termed 

 " merozoites." Another view, however, is that schizogony is here witnessed 

 in its simplest form, and this seems the better view to take. 



