204 I'ROTOZOOLOGY 



With stigma Family 1 Euglenidae 



Without stigma 



With 1 flageUum Family 2 Astasiidae (p. 209) 



With 2 flagella Family 3 Anisonemidae (p. 212) 



Family 1 Euglenidae Stein 



Body plastic ("euglonoid"), but, as a rule, more or less spindle- 

 shaped during movement; the majority possess a single anterior 

 flagellum (with the exception of Eutreptia and Euglenamorpha) ; 

 green (sometimes red) chromatophores (except one genus) and 

 stigma occur, though in some cases absent; metabolic products 

 oil and paramylon; asexual reproduction by longitudinal fission 

 in either active or resting stage; mostly freshwater inhabitants. 



Genus Euglena Ehrenberg. Short or elongated spindle, cylin- 

 drical, or band-form; pelhcle usually marked by longitudinal or 

 spiral striae; some highly plastic with a thin pellicle; others regu- 

 larly spirally twisted; stigma usually anterior; chromatophores 

 numerous and discoid, band-form, or fusiform; pyrenoids may or 

 may not be surrounded by starch envelope; metabolic products 

 paramylon bodies which may be two in number; one being located 

 on either side of nucleus, and rod-like to ovoid in shape or 

 numerous and scattered throughout; contractile vacuoles small, 

 near reservoir; asexual reproduction by longitudinal fission; 

 sexual reproduction reported in Euglena sanguinea; common in 

 stagnant water, especially where algae occur; when present in 

 large numbers, the active organisms may form a green film on the 

 surface of water and resting or encysted stages may produce 

 conspicuous green spots on the bottom of pond or pool; in fresh 

 water. Numerous species. 



E. pisciformis Klebs (Fig. 95, a). 25-30^ by 7-1 0^; spindle- 

 form, with bluntly pointed anterior and sharply attenuated 

 posterior end; slightly plastic; highly active; paramylon indis- 

 tinct; chromatophores lateral and discoidal; 2 pyrenoids; 

 flagellum fairly long. 



E. viridis Ehrenberg (Fig. 95, 6). 50-60/i by 14-18/x; anterior 

 end rounded, posterior end pointed; spindle-shaped during 

 motion, highly plastic when stationary; pellicle obhquely 

 striated; chromatophores more or less band-form, arranged in a 

 stellate form; nucleus posterior; nutrition holophytic, but also able 

 to carry on saprozoic nutrition, during which period chromato- 

 phores degenerate. 



