FAMILY: CERCOMONADID^ 629 



fowl flagellate, and finds that only four flagella are present, and that it has 

 the characteristic structure of members of the genus Chilomastix. In the 

 form figured by Martin and Robertson the cytostomal fiagellum was 

 evidently in an unusual position outside the cytostomal cleft. Fonseca's 

 genus, Tetrachilomastix, thus becomes a synonym of Chilomastix. San- 

 giorgi (1917) placed in this genus as T. intestinalis a flagellate he saw in 

 human fseces. It had four anterior flagella and was cultivated. There 

 is no evidence that it was not a Trichomonas. 



Chatterjee (1923) has given the name Tetrachilomastix bengalensis to a 

 flagellate which he says occurs commonly in the human intestine in India. 

 According to his description, it has the general structure of a Chilomastix, 

 but differs in that there are four anterior flagella, while a fifth runs along 

 the border of an undulating membrane situated at one side of the large 

 cytostomal groove. The attached axoneme may extend posteriorly as 

 a flagellum. Through the courtesy of the author the writer has been 

 able to examine preparations of the flagellate, and he is quite unable to 

 convince himself that the organism differs in any essential respect from 

 C. mesnili. It appears to him that the undulating membrane is merely 

 the edge of the fold which occurs in twisted forms. The fixation of the 

 flagellates and the cysts was not entirely satisfactory. 



7. Family: CERCOMONADID^ Kent, 1880. 

 This family includes flagellates which may be supposed to have 

 originated from flagellates of the Heteromita type in which the trailing 

 flagellum has become attached to the surface of the body. In addition 

 to the attached flagellum, which is posteriorly directed, there are one or 

 more free anteriorly directed flagella. 



A. Cercomonadidse with One Anterior Flagellum. 



Genus: Cercomonas Dujardin, 1841. 

 The members of this genus have two flagella, which arise from the 

 anterior end of the body. One flagellum is directed forwards as a free 

 flagellum, while the axoneme of the other turns backwards over the 

 surface of the body to which it is attached. It becomes a flagellum at the 

 posterior end of the body. Though the name Cercomonas has been 

 frequently used to designate intestinal flagellates of man, these have 

 belonged to other genera, such as Trichomonas and Chilomastix. The 

 flagellates of this genus are common in infusions, where they were first 

 seen and named by Dujardin (1841). They also appear in old faeces 

 as coprozoic organisms, but there is no evidence that they are ever para- 

 sitic in the human intestine. Some observers, as, for instance. Porter 

 (1918), record them as occurring in the human stool, but it is probable 



