PROTOMONADINA 



247 



Fig. 114. a, Trypanosoma gambiense (5 individuals) and a human 

 erythrocyte; b, T. cruzi; c, T. hrucei; d, T. theileri; e, T. vielophagimn ; 

 f, T. evansi; g, T. equinum; h, T. equiperdum, all X 1000 (various in- 

 vestigators) . 



T. theileri Layeran (Fig. 114, d). Non-pathogenic large tryp- 

 anosome which occurs in blood of cattle; sharply pointed at 

 both ends; 60-70/x long; myonemes are well developed. 



T. americanum Crawley. In American cattle; probably iden- 

 tical with T. theileri; transmitted from cattle to cattle by tabanid 

 flies. 



T. melophagium (Flu) (Fig. 114, e). Non-pathogenic trypano- 

 some of the sheep; 50-60yu long with attenuated ends ; transmitted 

 by Melophagus ovinus. 



T. evansi (Steel) (Fig. 114,/). In horses, mules, donkeys, cattle, 

 dogs, camels, elephants, etc.; infection in horses seems to be usu- 

 ally fatal and known as "surra"; about 25/ilong; monomorphic; 

 transmitted by tabanid flies; widely distributed. 



T. equinum Vages (Fig. 114, g). In horses in South America, 

 causing an acute disease known as "mal de Caderas"; other do- 

 mestic animals do not suffer as much as do horses; 2()-25fx long; 

 without blepharoplast. 



T. equiperdum Doflein (Fig. 114, h). In horses and donkeys; 

 causes "dourine," a chronic disease; widely distributed; 25-30)u 

 long; no intermediate host; transmission takes place directly from 

 host to host during sexual act. 



T. lewisi (Kent) (Figs. 113; 114, i). In blood of various species 

 of rat; widely distributed; non-pathogenic under ordinary condi- 

 tions; about 25/x long; very active; slender; with a long flagellum; 



