4o8 



TR VP A NO SO MID ^ 



B. Monomorphic trypanosomes with non-granular cytoplasm. 

 Spread by tsetse-flies, in which development is confined 

 to the proboscis and hypopharynx. (This group agrees 

 with the genus Duttonella.) 



I . Kinet onucleus large and terminal . Undulating mem- 

 brane poorly developed and simple. Movements 

 very rapid — T. vivax, T. capm, T. uniforme. 

 (Vivax sub-group.) 

 II . Kinet onucleus prominent and subterminal. Undulat- 

 ing membrane well developed . Movements active^ — 

 T. pecorum and T. simicB. (Pecorum sub-group.) 



Taking into consideration the above, we may arrange the patho- 

 genic mammalian trypanosomes as follows: — 

 A. Classifiable: — 



I. Genus Castellanella. 



Genus Castellanella Chalmers, 1918. 



Definition, — Trypocastellanellese with the definitive host a fly and 

 the intermediate host in a warm-blooded vertebrate. Without 

 reproduction by schizogony in the vertebrate host, in which it is 

 polymorphic, with granular cytoplasm, small kinetonucleus, and 

 well-developed undulating membrane. Final stage in the definitive 

 host is in the salivary glands. Infection is inoculative and trans- 

 mission is ingestive (see Chapter XXXV., p. 878). 



Co-Type Species. — Castellanella gamhiensis (Dutton, 1902) and Castellanella 

 castellanii (Kruse, 1903). 



Other Species. — The species of the genus may be differentiated as follows : — 



A. Posteriorly nucleate in rats : — 



I. Will not infect man. Kills an animal immunized against 

 C. rhodesiensis — C. brucei. 

 II. Infects man. Kills an animal immunized against C. brucei — 

 C. rhodesiensis. 



B. Not posteriorly nucleate in rats : — 



I. Infection direct from vertebrate host to vertebrate host during 



coitus — C. equiperdum. 

 IT. Infection by means of a definitive host: — 



(a) Definitive host not a tsetse-fly — C. evansi. 



[b) Definitive host a tsetse-fly: — 



1 . Causes chronic and often mild infections in man — 



C gambiensis. 



2. Causes acute and severe infections in man— C. castellanii. 



II. Genus Duttonella. 



Genus Duttonella Chalmers, 1918. 



Definition, — Trypocastellanelleae with definitive host in a fly and 

 intermediate host in a warm-blooded vertebrate. Without repro- 

 duction by schizogony in the vertebrate host, in which it is mono- 

 morphic, with non-granular cytoplasm, a large kinetonucleus, 

 which may be terminal or subterminal, with or without a well- 



