THE H^MOPLAGBLLATES. 



297 



attenuated and filiform (fig. 49, la). On their part, Dutton and Todd 

 figure a distinct free portion of tlie flagellum in all their types (II), it being 

 short in the tadpole-like and stumpy forms, but long and well-developed 

 in the large (adult.'') ones. Reconciliation between these two views must 

 await further research. T. dimorphon causes marked trypanosomosia 

 of horses in Senegambia ; these animals are few in number in that colony 

 and mostly imported. Tlie short forms are met with in the earlier stages 



Fig. 49. — T. dimorphon. I, after Lav. and Mesn. ; a, long 

 form, b, short form. II, after Dutton and Todd ; a, tadpole- 

 form, b, stumpy form (from a rat), c, stumpy form dividing, d, 

 long form. X 1500. 



of the malady, the long ones occurring later. The " natural " Vertebrate 

 host is not known. The transmitting Insect is, possibly, Glossina 

 palpalis, which is abundant in the district, but it should be added that 

 Dutton and Todd's endeavours to artificially transmit the parasites to rats 

 by this means were unsuccessful. 



T. theileri, Laveran,^ and T. transvaaliense, Laveran, 1902. These 

 two forms are considered together, since it is uncertain whether they do 

 not really both belong to one species, which would bear the former name. 

 T. theileri (fig. 50 a and b) is the largest known Mammalian Trypano- 



' Laveran (32) named the parasite on the 3rd March, 1902, and Bruce 

 (7) on the 8th of the same month. 



VOL. 50, PART 2. NEW SERIES. 21 



