GENUS: CHILOMASTIX 621 



Genus: Chilomastix Alexeieii", 1910. 



Alexeiefl (1909) described as Macrostoma caulleryi a flagellate of this type from 

 the intestine of tadpoles, and it was in this genus that the writer (19106) placed 

 the human form as M. niesniU. It was later discovered that the name A[ aero stoma 

 was not available, so Alexeieff (1910) included the flagellate in Perty's genus 

 Tetramitus. It was evident, however, that the parasitic forms were not of the 

 same type as the free-living Tetramitus, so Alexeiefl (19126) established the new 

 genus, Chilomastix, by which name these forms are now generally known. 



The flagellates of this genus have pear-shaped bodies, three anteriorly 

 directed flagella, and a large cytostomal cleft, within which is a fourth 

 flagellum. There is a vesicular nucleus near the anterior end of the body, 

 and between it and the anterior end of the cytostomal cleft is a group of 

 blepharoplasts which give origin to the four flagella and to two filaments 

 which pass along the margins or lips of the cytostomal cleft. Reproduc- 

 tion is by longitudinal division. Characteristic pear-shaped cysts are 

 produced. In each cyst there is a single flagellate, of which the nucleus, 

 cytostomal cleft, and blepharoplasts can often be clearly distinguished. 



CHILOMASTIX IN MAN. 



Chilomastix mesnili (Wenyon, 1910).— As pointed out by Brumpt (1912rt) 

 and ('Jialmers and Pekkola (1917), Davaino (1854) was the first observer to mention 

 this flagellate. In 1860 he redescribed and figured it. Though his figures were 

 imperfect in that only a single anterior flagellum was shown, his statements regarding 

 the cytostomal cleft render it very probable that he was actually dealing with this 

 organism. He referred to it as Gercomonas liominis variety A, the variety B being 

 TrieJiomonas. In the same year Moquin-Tandon (1860), some months before the 

 ai^pearance of Davaine's work, referred to the latter's two varieties of Gercomonas, 

 the account of which had not then been published. He must have had some know- 

 ledge of Davaine's forthcoming work, for, though he did not give any recognizable 

 description or figures of the flagellates, for the variety " A " he proposed the name 

 Gercomonas davainei, and for the variety "B" the name Gereomonas obliqua. It 

 seems clear that if there is no doubt as to the identity of Davaine's flagellates, the 

 correct name for the human GMlomastix, as pointed out by Kofoid (1920), should 

 be GMlomastix davainei Moquin-Tandon, 1860, while that of the human intestinal 

 Trichomonas should be Trichomonas obliqua Moquin-Tandon, 1860. It seems un- 

 desirable, however, to change the name Ghilomastix mesnili, which is now in general 

 use, and though it is very jirobable that Davaine was actually observing this flagel- 

 late, his description would have been quite madequate to establish its identity 

 were it not for the fact that the human intestine harbours only a limited number 

 of organisms of distinctive structure. Davaine's description might apply to Emba- 

 domonas intestinalis, which, however, is a much rarer organism than Ghilomastix 

 mesnili. Cunningham (1871) in India, Marchand (1875), Leuckart (1879), Grassi 

 (1881a), Epstein (1893), Roos (1893), and others probably saw this flagellate, but 

 they did not describe it accurately, and confused it with Trichomonas. It must 

 have been frequently referred to as Gercomonas, a name which was formerly employed 

 by medical writers as a general name for any flageUate of the human intestine. 



The flagellate named by Prowazek (1911) Fanapepea intestinalis, that by Pro- 

 wazek and Werner (1914) Gijathomastix liominis, and that by Gabel (1914) Difcimus 



