stokes.] 04:^ [Nov. 2, 



This form differs from U. farctus C. & L., in the presence of the mul- 

 tiple contractile vesicles and in the single, rounded nucleus, the latter in 

 E. farctus being recorded as band-shaped. 



The infusorian was obtained in abundance in a gathering made in the 

 middle of February in the mild winter of 1889-'90. Reproduction is by 

 transverse fission. 



Nassula trichocystis, sp. nov. (Fig. 11). — Body elongate-cvate or 

 subelliptical, cylindrical, more than twice as long as broad, the two 

 extremities subequal ; oral aperture near the anterior extremity, in a 

 slight depression or concavity of the lateral body-margin, and followed by 

 a conspicuous, conical, pharyngeal rod-fascicle extending to near the 

 body-centre ; oral cilia somewhat larger and more conspicuous than those 

 of the general surface ; contractile vesicle single, spherical, laterally 

 placed in the posterior part of the anterior body-half, often leaving small 

 lacunai at complete systole ; nucleus subspherical, subcentrally located ; 

 trichocysts exceedingly abundant, obliquely and densely set within the 

 cortical layer ; endoplasm frequently exliibiting a movement of rotation. 

 Length, -gig inch. Hab. — Pond water, near Short Hills, N. J. Move- 

 ments rotary on the longitudinal axis. 



This form, which is interesting on account of the remarkable abundance 

 of trichocysts enclosed by the cortex, was collected by Mr. H. C. Wells, 

 of Short Hills, N. J., and by him sent to me. 



Urostyla vernalis, sp. nov. (Fig. Vi). — Body elongate-ovate, or sub- 

 elliptical, soft and flexible, about three times as long as broad, both 

 extremiliies rounded, the anterior somewhat curved towards the left-hand 

 side and slightly narrowed ; posterior extremity sometimes evenly convex, 

 frequently obtusely pointed on the right-hand side of the median line ; 

 dorsal aspect convex, its cuticular surface irregularly roughened by 

 clusters of minute, rounded elevations arranged in irregularly longitudinal 

 series ; lateral body- margins of the larger infusorians often flattened and 

 subparallel, those of the smaller forms convex ; upper lip crescentic ; 

 peristome field obovate, the anterior region of the adoral depression proper 

 not including any portion of the frontal border, but taking its origin pos- 

 teriorly to that margin, at a distance about equal to one-tenth the length 

 of the entire body, and extending on the left-hand side of the body some- 

 what obliquely backward towards the right-hand side for about one-third 

 the length of the ventral surface, its left-hand margin bearing a series of 

 large and conspicuous adoral cilia, and a row of finer par-oral cilia, the 

 right-hand border supporting an undulating membrane and a series of fine 

 pre-oral cilia ; endoral cilia none ; uncinate frontal styles from four to six, 

 distally bifid and somewhat irregularly placed near the right-hand border 

 of the peristome field ; ventral surface clothed by fine, vibratile cilia in 

 six parallel, longitudinal lines ; marginal setiE longest, largest and most 

 conspicuous on the posterior border, where they are slightly interrupted, 

 those on the two sides of the median line of the body usually directed 

 towards one another and frequently overlapping ; anal styles slender, 



