the body. The right edge of the peristome supports an undulating
membrane. The nucleus is moniliform and extends the full length of
the left side; a number of micronuclei are distributed along its
course (Maupas).

Length 400µ; diameter at widest part 105µ. Maupas gives the length
from 305µ to 495µ; and Stein 376µ to 564µ. Very common.

For a more extended account of the structures, see the excellent
description by Maupas '83.


[Illustration: Fig. 45.--_Condylostoma patens_.]


KEY TO THE MARINE GENERA OF STENTORIDÆ.

Diagnostic characters: The peristome is relatively short and limited
to the front end of the animal, so that its plane is nearly at right
angles to that of the longitudinal axis of the body. The adoral zone
of cilia either passes entirely around the peristome edge or ends at
the right-hand edge. The surface of the peristome is spirally
striated and provided with cilia. Undulating membranes are absent.

1. Peristome circular in outline; Genus _Stentor_
limited to the anterior end

2. The peristome is drawn out into two Genus _Folliculina_
wing-like processes; tube-dwelling