1897] MICROSCOPICAL JOURNAL 113 



This infusorial! has been found by the writer in all 

 kinds of water, fresh and stale, in animal and vegetable 

 mac'erations ; sometimes in great abundance. The an- 

 terior flagellum is heavy and strap-like, and is differ- 

 ent from any appendage found on any of the tiagellata, 

 so far recorded. Tlie movements of this flagellum are 

 more like the wagging of the tail of a pleased dog than 

 the ordinary vibatile movements. 



At times this flagellum is bent backwards on either the 

 dorsum or ventrum and no matter how rapid the move- 

 ments are it does not in the least seem to accelerate the 

 even gliding movements of the body. While the writer 

 has observed a perceptible increase of the granules of 

 food in the endoplasm, he has never been able to detect 

 the inception of such food, but he has a strong presump- 

 tion that such inception takes place in the slight concav- 

 ity existing just behind the origin of the flagella on the 

 ventral surface. 



Family. — ParamonadidsB. S. K. 



Grenus. — Petatomonas. Stien. 



Species. — Petalomonas pusilla (fig. 5). 

 Body subovate, twice as long as wide ; flattened and 

 without a furrow or ridge ; Anterior slightly narrower 

 than the posterior ; both extremities rounded ; sinistral 

 border of greater convexity than dextral border; flagellum 

 equalling a little more than one body length and directed 

 forwards, in a straight line and stiff manner, the distal 

 end vibratile; contractile vesicle conspicuous and located 

 well forwards in the anterior body half and near to the 

 sinistral border ; nucleus round and situated, medianly, 

 in the posterior body half; Endoplasm, hyaline and 

 slightly granular posteriorly ; locomotion same as all 

 the species ; Size 1-3000 inch. Habitat — stale infusion of 

 aquatic plants. 



This form is evidently the smallest of the genus so far 

 recorded. Kent in his " Manual of the Infusoria" men- 



