ventral and dorsal surfaces are considerably arched and the latter
usually has a number of rows of longitudinal stripes. The open
peristome is broad and reaches back to the middle of the ventral
surface and beyond. According to Stein, the two edges can approach
each other, thus opening and closing the peristomial area. Its right
edge forms a greater angle with the front edge than in the genus
_Euplotes_, and the left edge forms a greater angle with the front
edge than in that genus. The left edge also appears to cover over the
adoral zone slightly. There are no ventral cirri in front, but on the
posterior ventral surface are 7 great springing cirri. Five of these
are inserted on the right aide in a deep in-sinking, and the other 2
in a similar depression on the left ventral surface. Above the 5
right-side cirri, _i.e._, dorsal to them, but in the same depression,
are 3 angular cirri. A few edge cirri are found to the left of them
and another to the right of the 5 cirri. The contractile vacuole is
on the left side between the main groups of cirri. The macronucleus
is band-form or spherical, and is situated in the middle region of
the body. Movement consists in forward swimming with sudden springs.

Salt water.


Uronychia setigera, n. sp. Fig. 55.

This species is very common in the Woods Hole waters. It is small,
colorless, and very active. The most characteristic feature is
the posterior end with its relatively enormous cirri, which are
apparently large enough for an animal four times its size. The form
is ovoid, widened posteriorly.