CLASSIFICATION OF THE MASTIGOPHORA 47 



Family Cercomonadidce: The organisms are frequently plastic and changeable in 

 form, but unable to form pseudopodia; there is but one flagellum with a 

 flagellum-fissure at the base ; nutrition is holozoic, saprozoic, or parasitic. 



Typical genera: Cercomonas, Dujardin, 1841 (a very uncertain genus); Herpe- 

 tomonas, Kent, 1880, ("including Donovan-Leishman bodies"); Crithidia, 

 Leger, 1904; Oikomonas, Kent, 1880; Copromonas, Dobell, 1908. 



Family Codonecidas: Small colorless monads which secrete and remain in gelati- 

 nous or membranous cups. 



Typical genera: Codoneca, James-Clark, 1866; Platytheca, Stein, 1878. 



Family Bikecidce: Minute organisms of peculiar shape, the basal broader portion 

 bearing a tentacle-like process; nutrition is holozoic; the individuals single 

 or colony forming. 



Typical genera: Bicoseca, James-Clark, 1867; Poteriodendron, Stein, 1878. 



Family Heteromonadidcc: Small colorless monads possessing one or more accessory 

 flagella in addition to the primary one; they frequently form large but delicate 

 colonies upon a common stalk. 



Typical genera: Monas, Stein, 1878; Dendromonas, Stein, 1878; Anthophysa, 

 St. Vincent, 1824; Rhipidodendron, Stein, 1878. 



Order 3. HETEROMASTIGIDA. A small group comprising various kinds of flagel- 

 lated forms which are sometimes naked and plastic, sometimes provided with 

 a highly differentiated membrane. The essential morphological characteristic 

 is the possession of two or more flagella, one or two of which are directed 

 downward and backward, while the other is directed forward and used in 

 locomotion. 



Typical genera: Bodo, Stein, 1878; Phyllomitus, Stein, 1878; Oxyrrhus, Dujar- 

 din, 1841 ; Anisonema, Dujardin, 1841 ; Trimastix, Kent, 1881. 



Order 4. TRYPAXOSOMATIDA. Organisms of elongate, usually pointed form, and 

 of parasitic mode of life; with one or two flagella arising from a special 

 "motor" nucleus, ami with an undulating membrane provided with myo- 

 nemes running from the kinetonucleus to the extremity of the cell; one of the 

 flagella is attached to the edge of this membrane throughout its length, and 

 may terminate with the membrane or be continued bevond the body as a free 

 lash. 1 



Typical genera: Trypanosoma, Gruby, 1841; Trypanoplasma, Lav. and Mesnil, 

 1904; Trypanophis, Keysselit/, 1904. 



Order 5. POLYMASTIGIDA. ( >rganisms characterized by numerous flagella, 

 frequently arranged in groups, and with one or many mouth openings usually 

 at the bases of the flagella. 



Tribe 1. Astomca. Organisms with many flagella uniformly distributed, and 

 without special mouth openings. 



Typical genera: Multicilia, Cienk., 1SS1; Grassia, Fisch., 1885. 



Tribe 2. Monostomea. Organisms with mouth opening at the base of the group 

 of from four to six flagella. 



Typical genera: Collodictyon, Carter, 1865; Trichomonas, Donne, 1837; Megas- 

 toma, Grassi, 1881; Tetramitus, Perty,lW2. 



Tribe 3. Distomea. Organisms with two mouth openings at the bases of the two 

 groups of flagella. 



Typical genera: Hexamitus, Dujardin, 1838; Trepomonas, Dujardin, 1839; Spi- 

 ronerna, Klebs, 1893; Urophagus, Klebs, 1893. 



!The conclusions of Novy, MacNeal, and Torrey (1907) that herpetomonas, crithidia, 

 and trypanosoma are synonyms cannot be accepted on the basis of cultural methods alone; 

 when the life history of these parasitic forms is known in detail will be time enough to speak 

 of synonyms, and as the important structural characteristic which the membrane represents 

 far outweighs the cultural characteristics, it is better to hold to the older view and thus to 

 prevent further complications in what is already almost a hopelessly complicated group. 



