PROTOMONADINA 



345 



opposite end, marking the outer boundary of the undulating 

 membrane; in most cases fiagellum extends freely beyond body; 

 many with myonemes; multiplication by binary or multiple fission. 

 The organism is carried from host to host by blood-sucking in- 

 vertebrates and undergoes a series of changes in the digestive system 

 of the latter (Fig. 142). A number of forms are pathogenic to their 

 hosts and the diseased condition is termed trypanosomiasis in general. 



Fig. 141. Diagram illustrating the morphological differences among the 

 genera of Trypanosomatidae (Wenyon) 



T. gambiense Dutton (Fig. 143, a-d). The trypanosome, as it oc- 

 curs in the blood, lymph or cerebro-spinal fluid of man, is extremely 

 active; body elongate, tapering towards both ends and sinuous; 15- 

 30/i by 1-3 ju; the small blepharoplast is located near the posterior 

 end; fiagellum arises from the blepharoplast and runs forward along 

 the outer border of somewhat spiral undulating membrane, extend- 

 ing freely; binary fission; between long (dividing) and short (recently 

 divided) forms, various intermediates occur; in man in central Africa. 



No other stages are found in the human host. When a "tse-tse" 

 fly, Glossina palpalis or G. tachinoides, sucks the blood of an in- 

 fected person, the trypanosomes remain in its stomach for a few 

 days and undergo multiplication which produces flagellates of 

 diverse size and form until the 7th to 10th days when the organisms 

 show a very wide range of forms. From 10th to 12th days on, long 



