536 The American Naturalist. [June, 
4, “ Endoral” cilia lining the gullet from the peristome-angle through 
the neck to the posterior part. 
5. A right marginal series extending from the anterior end to and 
over the neck; the cilia are rather short and somewhat remote from 
each other. 
6. A left marginal series, beginning to the left of the peristome and 
extending backward, somewhat oblique; the cilia are short and 
crowded, 
7. Two series of ventral cilia on the neck, betwenn 5 and 6, and pos- 
terior to the peristome. 
8. A short, oblique group or series of about six long, hair-like, stiff 
cilia, to the left and somewhat behind the peristome-angle, directed 
ventralward obliquely. 
9. A longitudinal series of cilia of the same kind along the left side 
of the neck. 
10. A similar series on thè right side ; in both these series the cilia 
are directed slightly backward when the animal is extended, and for- 
ward when it retracts. 
11. Fine, stiff, hair-like dorsal cilia or “tactile hairs,’ in several . 
series of various length ; quite short on the anterior processus, longer 
from the peristome backward; Nos. 9 and 10, and possibly, also, 8, 
may be of the same category. 
12, Some cilia near the posterior end of the body, whose exact group- 
ing and significance are yet to be ascertained. 
The size is subject to considerable variation ; long. of extended speci- 
mens 0:15-0:25 mill. 
It seems that the anterior part and neck are made up wholly of 
ectosarc, and the softer endosare fills the posterior bulbous part. 
The food consists of smallest particles, so far as observed, most bac- 
teria, etc., carried along with the current of water and gathered in the 
gullet at some distance from the peristome-angle, to a smaller or larger 
ball (fig. 1 f b) which is then passed backward. By the large membrane 
and the long, dense series of long “ paroral” cilia at the right margin 
of the peristome (fig. 2, um and par), standing out perpendicularly, a 
very effective wall is formed for conducting the current with the minute 
food particles to the peristome-angle. Larger objects are usually ex- 
pelled when driven into the peristome, by the posterior adoral cilia 
directed rather towards the right. But occasionally larger morsels, up 
to 0°01 mill. diameter, are swallowed. After digestion, the balls (fig. 
1, db) are passed forward through the neck, on the left side, to the 
anus (fig. 1, a) situated to the left of the peristome. While passing 
