344 



MASTIGOPHORA AND PROTOMONADINA 



Hartmann and Chagas met with it in Brazil. Since then it has only 

 been recorded once. 



Morphology." — ^The body is pear-shaped, measuring on an average 

 8-15 microns in length by 3-4 microns in breadth, but Wenyon has 

 met with small forms measuring only some 2-3 microns in greatest 

 length. 



Fig. yi —Cercomonas longicauda Dujardin, 1841. 

 Type with granules around the nucleus ; compare this with Fig. 74. 

 (After Wenyon, from the Quarterly Journal of Microscopical Science.) 



The cytoplasm is alveolar and contains a large anteriorly situate 

 nucleus, which has a liuclear membrane enclosing a clear space, in 

 which lies a large '.karyosome. The; nuclear membrane may be 

 drawn out into a cone, at the apex of which lies the granule— 

 blepharoplast — from which either the fiagella spring directly or a 

 single rhizoplast passes to the periphery and then divides into the 

 two fiagella . In any case, the fiagella arise from the anterior broader 

 end, and while one is directed forwards, the other passes posteriorly 

 over the surface of the body, to which it is attached until it reaches 

 the posterior end, when it becomes a free posterior fiagellum. The 

 cytoplasm also contains a^number of bright refractile granules. 



Fig, 72. — Cercomonas longicauda Dujardin, 1841. 

 Type without granules and Cyst. 

 (After Wenyon.) 



Life-History. — Simple fission, with division of the nucleus by 

 promitosis, takes place, while cyst formation is also known. 



The cysts measure some 6-7 microns in diameter. They are 

 slightly brownish spherical bodies containing a spherical central 

 nucleus surrounded by bright refractile granules. 



Pathogenicity. — It is believed to be non-pathogenic, aad to be 

 accidentally present in the faeces. 



