26 Infusoria from Fresh Water. [ January, 
stances just referred to, an inappreciable separation had probably 
taken place. 
The contracted body, when certain adjuncts of the entire col- 
ony are taken into consideration, affords some points that may be 
of diagnostic value. The creature probably affects running 
water, or water agitated by proximity to a current, but that it is 
restricted to the restless waters beating the shores of Luna island 
and pouring a resistless flood to make that terrific plunge, is not 
to be thought of; there only was its original habitat so far as the 
writer is concerned ; and when it is found, as it probably will be, 
in swift streams far beyond the sound of the “ Thunderer of the 
Waters,” its contracted form may offer some characters to aid in 
its identification. When the frontal region is folded together, 
and the whole body contracted, the zodid bears some resemblance 
to the bodies, when in a similar condition, of Opercularia plicatilis, 
described by the writer in the American Monthly Microscopical 
Journal for December, 1884. The anterior snout-like projection, 
the radiating cuticular elevations, the posterior annulations, are 
all similar. With the Zoothamnium, however, the conspicuously 
crenulated border of the projection and its longitudinal plications, 
of the Opercularia, are absent or obscure, while the radiating 
ridges on the shoulder of the Zodthamnium are much more 
prominent though fewer, and the posterior annulations, though as 
numerous, are less marked. 
The short, curved, band-shaped nucleus is constantly present 
in the anterior body-half, but its relative position is inconstant. 
At times its concavity is presented directly forward toward the 
ciliary disk, at others it is nearly perpendicular, with the convex- 
ity directed outwardly, and in rare instances it is transversely 
placed near the center of the body. 
A colony of this attractive infusorian is delineated in Fig. 8. 
The cuticular markings, as before intimated, are chiefly shown to 
emphasize the fact of their existence, not to exhibit their tenuity 
or number. 
Zoithamnium adamsi, sp. nov.—Body elongate-conical or conical-campanulate, 
twice as long as broad, widest anteriorly. tapering to the pedicel, and slightly con- 
stricted beneath the peristome border; cuticular surface very finely striate trans- 
versely; peristome border wider than the body, revolute; ciliary disk rounded and 
elevated ; contractile vesicle single, situated beneath the peristome border; nucleus 
short, band-like, curved and anteriorly placed; main rachis of the pedicel. usually 
bifureate, frequently quadrifid, occasionally tripartite; branches dichotomous, un- 
