138 THE PROTOZOA 



flagella, one being directed forward and used in locomotion, the others directed 

 backward and trailed after the organism. Nutrition is holozoic, and all of the 

 forms included are colorless. 



Family i. Bodonidae. Small naked forms in which there is only a slight difference, 

 if any, between the flagella. Genera : Bodo Stein ('78) ; Phyllomitus Stein 

 ('78) ; Colponema Stein ('78) ; Oxyrrhis Dujardin ('41). 



Family 2. Trimastigidae. With two accessory flagella. Genera: Dallingeria 

 Kent ('8 1) ; Trimastix Kent ( ? 8i). 



Order 4. POLYMASTIGIDA. The body is invariably without a shell, and is provided 

 with a delicate membrane, which allows more or less amoeboid movement. The 

 number of flagella varies from three to many, and the number of mouth open- 

 ings, or food-taking areas, likewise varies. Nutrition is holozoic. They increase 

 by longitudinal division. 



Tribe i. Astomea. Polymastigida with many flagella and without a mouth opening. 

 Genera: Multicilia Cienk. ( r 8i); Grassia Fisch ('85). 



Tribe 2. Monostomea. The anterior part is provided with a large mouth opening at 

 the base of the four or six flagella. Genera: Collodictyon Carter ('65) ; Tetra- 

 mitus Perty ('52) ; Monocercomonas Grassi ('8.2) ; Trichomonas Donne ('37) ; 

 Megastoma Grassi ('81). 



Tribe 3. Distomea. The flagella are separated into two symmetrical groups, with a 

 mouth area at the base of each group. Genera : Trigonomonas Klebs ('93) ; 

 Hexamitus Dujardin (""38) ; Trepomonas Dujardin ('39) ; Spironema Klebs ('93) ; 

 Urophagus Klebs ('93). 



Tribe 4. Trichonymphinea. Polymastigida, of unknown affinities, provided with 

 numerous flagella. They are parasites in the rectum of various hosts (Termites) . 

 Genera: Lophomonas Stein ('78); Leidyonella Frenzel ('91); Trichonympha 

 Leidy ('7?) ; Jcenia Grassi ('85) ; Pyrsonympha Leidy ('77). 



Order 5. EUGLENIDA. Large forms, having one or two flagella. a contractile or firm 

 body-wall, a mouth and pharynx at the base of the flagellum, and with a con- 

 tractile vacuole opening into the pharynx. They frequently form colonies and 

 are usually provided with chromatophores. Nutrition is holozoic, holophytic, or 

 saprophytic. 



Family i. Euglenidae. Elongate forms, with a more or less pointed end and usually 

 with one flagellum. The cuticle is marked with spiral stripings ; the contractile 

 vacuole, or vacuoles, open into a reservoir, which in turn opens into the pharynx. 

 A red eye-spot, or stigma, and green chromatophores, are usually present. 

 Within the body there are discoid, or, occasionally, band-formed chromatophores. 

 Paramylum granules are always present. Genera : Euglena Ehr. ('30) ; Colacium 

 Ehr. ('33) ; Eutreptia Perty ('52) ; Ascoglena Stein ('78) ; Trachelomonas Ehr. 

 ('33) ; Lepocinclis Perty ('49) ; Phacus Nitsch ('16) ; Cryptoglena Ehr. ('31). 



Family 2. Astasiidae. The body is elongate and usually has a striped membrane. 

 The anterior end is similar to that of Euglena, but there is no eye-spot. The 

 body is invariably colorless. Nutrition is saprophytic. Genera: Astasia Ehr. 

 (38) ; Distigma Ehr. ('31) ; Rhabdomonas Fres. ('58) ; Menoidium Perty ('52) ; 

 Atractonema St. ('78) ; Sphenomonas Stein ('78). 



Family 3. Peranemidae. The body is either stiff or plastic, and usually symmetrical. 

 The anterior end bears either one or two dissimilar flagella, which are more or 

 less deeply sunk in the body. A distinct mouth is found at the base of the 

 flagella. Nutrition is holozoic. Genera : A. With plastic body and one flagel- 

 lum : Euglenopsis Klebs ('93) ; Peranema Dujardin ('41); Urceolus Meresch- 

 kowsky ('77). B. With a plastic body and two flagella: Heteronema 

 Dujardin ('41); Dinema Perty ('76); Zygpselmis Duj. ('41). C. With a 

 constant body form and one flagellum : Scytomonas Stein ('78) ; Petalomonas 



