THE AMERICAN NATURALIST. [VOL. XXXV. 
one-fourth the length of the body; toes very 
small; a separate foot scarcely distinguishable. 
Eye near the caudal end of the brain, almost 
completely hidden by the dense opacity of the 
later . . 105, JV. truncata Jennings (Fig. 75) 
jz. Body San aah or sac-like, swollen behind 
kr. Very large and slow ; body sac-like, with a 
swollen neck, between which and the body is 
a constriction ; foot short ; toes minute 
106, JV. collaris Ehr. (Fig. 76) 
k2. Smaller; body subcylindrical ; head wide ; 
brain with a spherical opaque mass behind, 
bearing the eye, and connected by a tube with 
the front; foot very short, of two Re e 
small, bild a" in form. Length, . 
3m 07, N. aurita Ehr. re s 
£3. ns N. EA but smaller and more 
slender ; toes much longer and decurved ; the 
eye sometimes hidden by the opaque brain. 
Length about .15 mm. . . 108, W. cyrtopus 
Gosse (Fig. 78) 
j3. Body cylindrical, long, flexible, with a number 
of transverse constrictions and longitudinal folds, 
slightly tapering toward each end ; auricles two 
stalked spheres, with the cilia confined to the 
spheres; toes very small; brain long, cylindrical, 
opaque at the caudal end ; eye just in front of 
the opacity . . 109, W. Zerulosa Duj. (Fig. 79) 
(V. vorax Stokes would be characterized in t he same 
manner; it is probably a pics ii of N. torulosa.) 
(See also No. 62, N. monopus Jennings) 
No auricles, corona a ciliated ince oblique or 
extending onto the ventral surface ; brain clear ; body 
cylindrical or larviform, usually small Proales 
(A large, ill-defined genus, many of its American repre esenta- 
tives unidentified or undescribed. The following American 
species have been reported) 
hr. With a small decurved fleshy proboscis at the front 
ir. Parasitic in Vaucheria, forming galls ; body fusi- 
form ; toes small, straight, pointed 
110, P. w rneckii Ehr. 
i2. Free-swimming ; body cylindrical, iind fluted 
longitudinally ; proboscis large ; eye very large ; foot 
stout ; toes slender ; pointed . , P. felis 
Ehr. (Fig. 80) 
