348 MASTIGOPHORA AND PROTOMONADINA 



Tetramitus Perty, 1852. 



Callodictyon Carter, 1865. 



Costiopsis Senn, 1900. 



Chilomastix Alexeieff, 1911. 



Tetrachilomastix da Fonseca, 1915. 



Copromastix Aragao, 19 16. 



Tricercomonas Wenyon and O'Connor, 1917. 



Protetramitus Chalmers and Pekkola, 1918. 



And they may be differentiated as follows : — ■ 



A. Without cytostome : — 



1. With rhizoplast. (i) Protetramitus Chalmers and 



Pekkola, 1918. 



2. Without rhizoplast— (2) Copromastix Aragao, 1916. 



(3) Tricercomoms Wenyon and O'Connor, 1917. 



B. Cytostome probably present 



At all events, there is a deep ventral longitudinal furrow — 

 (3) Callodictyon Carter, 1865. 



C. Cytostome present 



I . Trailing flagellum is free : — 



{a) Body dorso-ventrally compressed, ventral surface 

 with deep depression which serves as a sucker 

 and contains the cytostome and two short free 

 flagella ; the two thick long trailing flagella issue 

 from this depression — (4) Costiopsis Senn, 1900. 



{b) Body more or less symmetrical and not compressed 

 or arranged as above, with three anterior and 

 one free trailing flagellum — (5) Tetramitus Perty, 

 1852. 



11. Free trailing flagellum absent: — ■ 



[a) Three anterior flagella — (6) Chilomastix Alexeieff, 



1911. 



(b) Four anterior — (7) Tetrachilomastix da Fonseca, 



1915- 



Of these genera we are only concerned with Copromastix, Tri- 

 cercomonas, Chilomastix, and Tetrachilomastix. 



Genus Copromastix De Beaurepaire Aragao, 1916. 

 Definition. — Tetramitidinae without cytostome and rhizoplast. 



Copromastix pro wazeki Aragao, 1916. 

 Found in cultures of human faeces in Brazil. 



Genus Tricercomonas Wenyon and O'Connor, 1916. 



Definition. — Tetramitidinae without cytostome and with three 

 anterior and one trailing flagellum. 



Remarks. — This genus is like Cercomonas in many ways, but 

 cannot be classified in the family Cercomonadidae ; and as it shows a 

 resemblance to Protetramitus, we place it here. 



