New American Infusoria. By Dr. A. C. StoJces. 699 



thickness and contour, the anterior flagellum short, fine, originating 

 from the left-hand angle of the truncate frontal margin, its length not 

 exceeding one-half that of the hody, its movements not rapid ; con- 

 tractile vesicle single, located near the posterior extremity ; endoplasm 

 often inclosing numerous granules. Length of body from 1/4500 to 

 1/2250 in. Habitat : Standmg pond water with Sjphagnum. Move- 

 ments slowly gliding. 



Cercomonas Jieterofilum, sp. nov. Fig. 7. 



Body ovate, obovate, or suboval, soft and changeable in shape, 

 about twice as long as broad; anterior border rounded; posterior 

 margin tapering and obtusely pointed; anterior vibratile flagellum 

 about one and one-half times as long as the body, the trailing caudal 

 prolongation subequal to the zooid in length; nucleus apparently 

 subcentral ; contractile vesicles two, one near the posterior extremity 

 close to the left-hand body margin, the other near the centre of the 

 right-hand side ; endoplasm finely granular. Length of body 

 1/2250 in. Habitat : Standing pond water with aquatic plants. 



Cercomonas la^sa, sp. nov. Fig. 8. 



Body obovate, about three times as long as broad, rounded and 

 widest anteriorly, tapering to the posterior extremity, where it is 

 continued as a flexible tail-like prolongation equalling or exceeding 

 the body in length, and not rarely extending and retracting a fine, 

 flexible filament ; anterior flagellum not equalling the body in length ; 

 contractile vesicle apparently single, subcentrally located ; endoplasm 

 finely granular and occasionally inclosing several small, dark-bordered 

 particles which change their position with the motion of the sarcode ; 

 zooid's movements slow and smoothly gliding. Length of body, 

 1/2250 in. Habitat : Pond water with decaying Sphagnum. 



Cercomonas undulans, sp. nov. Fig. 9. 



Body elongate obovate, from five to six times as long as broad, 

 much depressed, very soft, flexible and changeable in shape ; posterior 

 border tapering and terminating in a fine, flexible, tail-hke traiHng 

 appendage about one-third as long as the zooid; anterior border 

 rounded; vibratile flagellum slender, about one-third as longas the 

 zooid ; anterior extremity expanded, flattened, constricted behind the 

 rounded frontal border ; contractile vesicle single, near the posterior 

 extremity, close to one lateral border. Length of body 1/1800 in. 

 Habitat : An infusion of decaying Sphagnum. Movements by lateral 

 flexure and undulations of the soft body. 



Cercomonas mutahilis, sp. nov. Figs. 10, 11, 12. 



Body obovate, soft, flexible and changeable in shape, twice as long 

 as broad, the anterior border rounded ; the posterior extremity pointed, 

 soft and plastic, emitting one or more short, lobate, sarcodic extensions, 

 or one or more long, irregularly linear pseudopodic prolongations which 



