A. C. Stokes —Fresh-water Infusoria. 321 
flexible, widest posteriorly, tapering toward the anterior ex- 
tremity which is somewhat curved toward the ventral aspect ; 
the posterior margin obliquely and undulately rounded, the 
ventral border concave, the dorsal one irregularly convex, its 
‘ing two small, conical elevations; the cu- 
or more, the largest one postero-terminal, the others small and 
scattered ; nucleus moniliform, the nodules irregularly ovate, 
centrally situated; trichocysts apparently wanting. ng 
of body 1, inch. Habitat.—The bacterial pellicle on the sur- 
face of an infusion of dead leaves. 
he movements of this infusorian are slow and even, with 
incertain changes from one side to the other, and with equally 
“nexpected contortions consisting of indescribable twistings 
and foldings of the body. The creature’s remarkably irregular 
outline is made more so by the two little projections on the 
Posterior part of the dorso-lateral border. These are constantly 
Present, bué vary somewhat in size and form. What utilitarian 
h. change except of form took place. The normal contour o 
€ infusorian is shown in fig. 11. 
Spirostomum loxodes, sp. nov. 
eri 
°urved toward the left, with a short beak-like projection, the 
Posterior margin truncate; cuticular surface obliquely striate, 
the nodules ovoid; contractile vesicle extending through the 
“tire length of the right-hand border, with a conspicuous pos- 
terior dilatation; anal aperture postero-terminal. Length of 
yey as to 7, inch. Habitat—Pond water in Western New 
or 
