A. ©. Stokes—Fresh-water Infusoria. 47 
assumes the ovate form, when folds would become extinct and 
rods or fibrille more conspicuous, which is in fact the case. 
That an elastic membrane connects the rod-like constituents of 
‘ the passage, I have not been able to determine. My impres- 
sion, however, is that none exists, the pharynx being merely an 
elongated cage-like structure open at each end, its delicate 
bars aya only around the oral aperture 
ollowing minute creatures are also apparently unde- 
mitted. They are deliberate, but eccentric in their move- 
ments, with the additional eccentricity of appearing to oe 
k downward, having in that position the convex surface 
which an observer would at free glance decide to be the donate 
That it is in reality the ventral aspect is proven, it would seem, 
by the fact that the short, trailing flagellum not only takes its 
origin from a point on that surface, but is habitually held 
beneath the convexity. It is scarcely possible that a non- 
vibratile flagellum could be of much service as a drag or asa 
pivot on which to turn, as this infusorian turns, if carried above 
thedorsum. Yet the animal frequently moves with this convex 
oie directed poReerN although this is the less common posi- 
gitudinal channel or - depression extending from the apex to the 
a ig extremity, thus giving the infusorian, when seen “end 
or in transverse optical section, a concayo-convex outline, 
oniew hat like that of a longitudinal slice of a bean. This 
grooved surface is represented in fig. 
When moving through the water, ‘it advances in a direct 
course steadily and not rapidly for a few moments, when it 
quickly and abruptly turns aside at an acute angle, the long 
flagellum then being thrown into indescribable curves and flex- _ e 
ures, but in the general direction of the route to be taken. 
No distinct oral aperture is visible. On several occasions 
humerous minute green evannel presumably of food, have 
been noticed within the endo 
