1890.] I ^ [Stokes. 



single, situated in the posterior body-half ; endoplasm finely granular. 

 Length of body tz \jj inch. Hab. — Standing pond water. Movements 

 rapidly vibratory. 



Heteromita triangularis, sp. nov. Fig. 8. — Body ovate or subtriangu- 

 lar, depressed, smooth, twice as long as broad, the anterior border 

 obliquely truncate, sometimes slight^ concave, the shorter lateral border 

 often flattened ; the longer convex ; posterior extremity obtusely pointed; 

 anterior flagellum about one-half as long as the body, the posterior or 

 trailing appendage from two to three times the length of the zooid ; con- 

 tractile vesicle single, posteriorly situated near the longer lateral border ; 

 nucleus apparently represented by a small light spot near the centre of 

 the anterior body-half. Length of body from ^ z \^ to ^ ff7 inch. Hab. — 

 Standing pond water. 



Food seems to be engulfed chiefly near the anterior extremity, this 

 region surrounding the particle by an irregular outflow of endoplasm, the 

 zooid then becoming indescribably unsymmetrical in form. The anal 

 aperture is postero-terminal or nearly so. 



Macromastix (p-o-npoz, long ; fxaartz, lash), gen. nov. — Animalcules 

 free swimming, ovate, having three flagella arising near together, one 

 short, antero-terminal and vibratile, two opposite, lateral and trailing ; 

 food engulfed at any point on the surface. Inhabiting standing water. 



Macromastix. lapsa, sp. nov. Figs. 9 and 10. — Body ovate, about twice 

 as long as broad, the anterior region changeable in shape, that margin 

 rounded and often obliquely truncate, the posterior obtusely pointed ; ante- 

 rior flagellum short, arising from the centre of the anterior truncation, the 

 lateral appendages trailing, about three times as long as the body ; 

 endoplasm colorless, transparent ; contractile vesicle single, laterally 

 placed near the body centre ; nucleus not observed. Length ^stm 

 inch. Hab. — Standing pond water. 



This form is a member of the Trimastigidoe of Saville Kent, and resem- 

 bles most nearly the Dallingeria of the same authority, differing chiefly 

 in the diverse length of the flagella, these appendages in Dallingeria 

 being subequal. The lateral flagella of Macromastix arise from opposite 

 points nearer the frontal border than do the similar appendages of Dal- 

 lingeria, in the last named form arising from the lateral borders at some 

 distance from the frontal margin, and possessing adhesive power in the 

 distal extremities, nothing of the kind having been observed with the 

 present firm. Food is engulfed at any point of the surface. 



7'rachelomonas ceroicula, sp. nov. Fig. 11. — Lorica subspherical, 

 smooth, orange yellow in color ; anterior orifice with a thickened, slightly 

 projecting external border, and produced internally as a straight, cylin- 

 drical, chitinous tube about one-third as long as the diameter of the lorica, 

 its anterior border attached around the anterior orifice of the sheath, its 

 posterior or internal margin circular and free, the long flagellum of the 

 enclosed animalcule protruded through this internal, tubular passage, and 

 the body, when completely filling the lorica, surrounding the cylinder as 

 if pierced by it. Diameter of the lorica ji S s inch. Hab. — Pond water. 



