702 Transactions of the Society. 



contrr^ctile vesicles two, small, one placed on each side near the anterior 

 extremity ; endoplasm inclosing: nnmerons dark-bordered corpuscles. 

 Length of body l/(j40 in. Habitat: An infusion of dead leaves. 



Hexamita truncata, sp. nov. Fig. 21. 



Body broadly obovate, soft and changeable in shape, less than 

 twice as long as broad ; frontal border rounded, the posterior ex- 

 tremity usually constricted and prolonged as a short, somewhat 

 flattened extension with subparallel lateral borders, and a truncate 

 posterior margin ; anterior flagella four, arising from the body at some 

 distance from the anterior border, each extended rigidly at right angles 

 with the surface, the distal extremities more or less curved ; posterior 

 trailing flagella two, less than tbree times as long as the body, each 

 arising from a lateral border of the posterior truncate prolongation ; 

 contractile vesicles two, placed near the origin of the posterior body 

 extension ; endoplasm granular ; movements rotatory on the longi- 

 tudinal axis. Length of body 1/2250 in. Habitat : Standing water, 

 with Sphagnum. 



Petalomonas orbicularis, sp. nov. 



Body suborbicular or broadly ovate, the length but slightly ex- 

 ceeding the breadth, much depressed, the lateral borders curved 

 toward the ventral aspect, so tbat the dorsal surface is evenly convex, 

 the ventral concave ; lateral and anterior borders rounded, the anterior 

 slightly emarginate centrally, the posterior extremity rounded or 

 slightly tapering and obtusely pointed ; flagellum subequal to the 

 body in length ; oral aperture distinct, apparently followed by a short 

 pharyngeal passage ; nucleus spherical, subcentrally located ; con- 

 tractile vesicle single, placed in the median line in close proximity to 

 the pharyngeal passage ; endoplasm often inclosing numerous dark- 

 bordered, probably amylaceous corpuscles, which slowly change their 

 position. Length of body 1/1500 in. ; greatest width 1/1285 in. 

 Habitat : Standing pond water, with Sphagnum. Movements rotatory 

 on the longitudinal axis. 



Atractonema pnsilla, sp. nov. Fig. 22. 



Body subcylindrical, from 3-5 times as long as broad, curved 

 toward the lower or ventral surface, the dorsal aspect evenly convex, 

 the opposite or ventral border concave, the surfaces longitudinally 

 traversed by from 6-8 straight or slightly oblique furrows ; frontal 

 margin slightly emarginate, the posterior border rounded ; flagellum 

 subequal to the body in length ; endoplasm colourless, often inclosing 

 near the extremities of the body several dark-bordered, probably 

 amylaceous corpuscles ; contractile vesicle single, near the centre of 

 one lateral border ; pharyngeal passage small but distinct. Length 

 of the body 1/1000-1/1200 in. Movements rotatory on the longi- 

 tudinal axis. Habitat : Standing water with decaying Sphagnum. 

 Eeproduction by longitudinal fission. 



