FLAGELLATE PROTOZOA (MASTIGOPHORA) 



251 



59 (S8) 



62 (69) 



63 (68) 



64 (6S) 



Body obovate, obliquely truncate in front; or subpyriform or sub- 

 spherical with a rounded front. . . Tetramitus Party. 

 Representative species. . Tetramitus variabilis Stokes 1886. 



Body changeable in form. Kagella subequal, inserted near the middle of the an- 

 terior border. Endoplasm granular. Contractile vacuoles two, near the front 

 border. Food received at any portion of the surface. Length 18 to 25 /«. Stand- 

 ing water with decaying vegetation. 



Fig. 389. Tetramitus variabilis. X 250. (After Stokes.) 



6S (64) 



66 (67) 



Chromatophores usually present. 



Flagella one or two. 



Order Euglenida 



61 



Elongated forms usually with pointed posterior ends. Chromato- 

 phores usually green. ParamyKn bodies present. 



Family Euglenidae . 62 



Naked or with very thin cuticle. ... -63 



Flagellum single 64 



Attached by a branched stalk, usually surrounded by a jeUy-Kke en- 

 velop . Colacium Ehrenberg. 



Representative species. Colacium steinii Kent 1880. 



So far as has been determined, no members of this genus have been reported in 

 North America. Several species have been reported in Europe. Usually 

 attached to Cyclops or other fresh-water crustaceans. 



Fig. 390. Colacium steinii. X 350. (After Kent.) 



Not attached and not surrounded by a jelly-like envelop. Large 

 forms, spindle-shaped, usually green, with an eye-spot. 



Euglena Ehrenberg . . 66 



Body rounded anteriorly, surface smooth. 



Euglena viridis Ehrenberg 1830. 



Body usually rounded anteriorly with a colorless, tail-Uke posterior pro- 

 longation. Surface smooth. Nucleus central; contractile vacuole anterior. 

 Length 50 to 75 u. Common. The chlorophyl may at times be lost and 

 the species, no doubt, may then exist on organic substances. 



Fig. 391. Euglena viridis. cv, contractile vacuole; n, nucleus; pam, paramylum; 

 st, stigma. X 400. (After Blochmann.) 



67 (66) Body cylindrical; surface beaded. 



Fig. 398. Euilma spiroiym. X soo. (After Conn.) 



Euglena spirogyraYjh.TtVihtxg 1830. 

 Body elongate, cylindrical, with a 

 pointed, tail-Uke prolongation. Periphery 

 covered by obhque rows of minute bead- 

 like elevations. Color bright green. 

 Nucleus central, with an elongated starch- 

 like body anterior and posterior to it. 

 Eye-spot near the base of the flagellum. 

 Length 100 to 200 |i. Among algae. 



