THE HiEMOFLAGELLATBS. 



293 



dromedaries, and wliich appears to be transmitted by another Tsetse-flj, 

 namely, G. longipennis (locally termed the " Aino "), is probably also a 

 variety of Nagana (see Brumpt [9 a]). 



T. evansi (Steel, 1885). (Syn. Spirochista evansi. Steel.) Length 

 about 25 n, breadth about Ih ju. This parasite (figs. 42 a, 45) is, morpho- 

 logically, very like T. brucii. It is generally rather more slender than 

 that form, and the anterior end rather more tapering and usually acutely 

 conical. Moreover, the free part of the flagellum is slightly longer in T. 

 evansi, and the cytoplasm lacks the prominent granules of T. brucii. 

 T. evansi also performs greater and more rapid movements of displace- 

 ment than the Nagana parasite. Natural hosts uncertain ; (V.) perhaps to 



Fig. 44. 



Fig. 45. 



Fig. 46. 



Fig. 47. 



Fig. 44. — T. brucii (after Bradf. and Plim.). 

 Fig. 45. — T. evansi. X 2000. (Original, from a preparation 

 of the blood of a mule, kindly lent by Mr. Plimmer.) 

 Fig. 46. — T. equiperdum. (After Lignieres.) 

 Fig. 47. — T. equinum. (After Lignieres.) 



be found among indigenous Bovida?, and (I.) is probably a Tabanus, 

 T. tropicus and T. lineola having been suggested (Rogers [92, 92 a]) ; 

 in Mauritius the epidemic is thought to have been spread byStomoxys 

 nigra. The cause of Surra in Indo-Burmah, which is particularly dan- 

 gerous- to Equidse. The disease is less fatal to cattle than Nagana is. 

 Various other animals also liable. The malady has been recently imported 

 into Mauritius and the Philippines. 



The illness known as " Mbori," occurring among dromedaries coming 

 from the Sahara into the Soudan (Timbuctoo, etc.), which is apparently 

 also conveyed by a Tabanus, is considered both by Vallee and Panisset 



