294 H. M. WOODCOCK. 



(117 a) and Laveran and Mesnil (54 a) to be a milder form of Surra, the 

 parasite which causes it being a " race " of T. e vansi. 



T. equiperdum, Dofl., 1901. (Syn. T. rougeti, L. and M.) Length 

 25-28 /i, breadth lh-2fi; slightly smaller than T. brucii. Also difEers 

 from that species in not having prominent grains in the cytoplasm. The 

 kinetonucleus is relatively large and well-developed (figs. 42 c and d, 

 46). This form has been the least studied of the better known patho- 

 genic ones. The cause of Dourine in horses in Algeria and in certain parts 

 of Southern Europe (chiefly the Mediterranean littoral). The infection is 

 transmitted (invariably?) during the act of coitus, and this explains 

 why mules and geldings are exempt. In the case of roving (wild) asses 

 the illness is usually slight, and the parasites are apparently more or less 

 latent, but whether these animals constitute the true Vertebrate host or 

 not cannot at present be said. Moreover, it is not yet certain whether the 

 parasites in the natural conditions have any alternate Insectan host into 

 which they must pass at intervals in order to complete the life-cycle. (See 

 also p. 280, footnote.) 



There appear to be one or two other varieties of trypanosomosis in 

 Northern Africa (Algeria). Thus, Sergent (101 a) announces a malady of 

 dromedaries, which is very similar to Mbori ; and Kennes(91), and Eouget 

 (93, 93 a) and others seem unable to decide whether there is a trypanoso- 

 mosis of horses, distinct from Dourine. 



T. equinum, Voges corr., 1902. (Syn. T. elmassiani, Lignieres.) 

 Length 22-25 /*, breadth 1^-2 /t. A morphological character which sharply 

 distinguishes this species from the rest — and which may ultimately prove 

 to be of more than specific importance — is the very minute size of the 

 kinetonucleus (figs. 42 E, 47). Cytoplasmic grains present, but not so 

 numerous as in T. brucii. In shape and details of form this parasite much 

 resembles T. e vansi. The Vertebrate host is most probably Hydro- 

 chcerus capybara; the transmitting Insect perhaps a Tabanid (many 

 workers have considered a Stomoxys, either S. nebulosa or S. cal- 

 citrans, to be the carrier, but Lignieres and Elmassian and Migone think 

 otherwise). T. equinum causes the destructive disease of horses known 

 as Mai de Caderas in Brazil, Argentina, and Central South America. 



T. garabiense, Dutt., 1902. (Syn. T. ugandense,' Castellani,T. castel- 

 lan ii, Kruse.) Length 21-23 /i, breadth 11-2 /«. Tliis species (fig. 48) is, 

 according to its average size, one of the smallest yet found. The parasites in 

 the blood frequently exhibit slight morphological differences from those in 

 the cerebro-spinal fluid. The former are somewhat longer and more slender, 



' The specific name ugandense was the one first given to the parasite 

 found in sleeping-sickness cases, Button's name having been previously 

 conferred on the form originally found in cases of human trypanosomosis 

 (Trypanosoma fever). See next page. 



