59 (58) 



60 (37) 



61 (87) 



62 (69) 



63 (68) 



64 (65) 



65 (64) 



FLAGELLATE PROTOZOA (MASTIGOPHORA) 251 



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

 spherical with a rounded front Tetramitiis Perty. 



Representative species Tetramitus variabilis Stokes i^^b. 



Body changeable in form. Fiagella 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 m- Stand- 

 ing water with decaying vegetation. 



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



Chromatophores usually present. Fiagella one or two. 



Order Euglenida . . 6 1 



Elongated forms usually with pointed posterior ends. Chromato- 

 phores usually green. Paramylin bodies present. 



Family Euglenidae . . 62 



Naked or with very thin cuticle 63 



Flagellum single 64 



Attached by a branched stalk, usually surrounded by a jelly-like en- 

 velop Colaciuni Ehrenbcrg. 



Representative species Colaciuni stein ii 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. Colaciuni steinii. X 350. (.^fter Kent.) 



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

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



Euglena Ehrenbcrg . . 66 



66 (67) Body rounded anteriorly, surface smooth. 



Euglena viridis Ehrenbcrg 1830. 



Body usually rounded anteriorly with a colorless, tail-like iwsterior pro- 

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

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

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



Fig. 391. 



Euiilena viridis. cv, contractile vacuole; n, nucleus; pant, paramylum; 

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



67 (66) Body cylindrical; surface beaded. Euglena spirogyra Ehrcnhcrg 1S30 



392. Euglena spirogyra. X 500- (After Conn.) 



Body elongate, cylindrical, with a 

 jxjinted, tail-like prolongation. IVriplury 

 covered by oblicjue rows of minute l>cad- 

 like elevations. Color bright green. 

 Nucleus central, with an clongate<i starch- 

 like body anterior and jxistcrior to it. 

 Kye-spot near the base of the llagcllum. 

 Length 100 to 200 n. Among algae. 



