A. C. Stokes—Fresh-water Infusoria. 327 
Dextorrtcna (deS205, on the right-hand side, rptyiov, a little 
hair), gen. nov. 
_Animalcules free-swimming, persistent in shape, entirely 
ciliate, elongate-ovate or subreniform, rounded _ posteriorly ; 
0 
In several structural points, in one attribute especially, the 
from 
al Known animaleules. Its ordinal position is with the Hete- 
rotricha, and when a systematic treatise shall be written on our 
peristome field, and especially in the presence of the row of 
adoral cilia on the right-hand side instead of the left, and in 
the presence of a ciliated pharynx, a feature to be distinguished 
only under high amplification and the most favorable position 
48 broad, the ace bearing minute, hemispherical pro- 
tuberances which give the infusorian, in optical section, a 
renulate outline; both extremities rounded, the posterior 
nding from the right-hand margin of the oral aperture ob- 
liquely backward and transversely across the right-hand side of 
Median line; endoplasm enclosing numerous small corpuscles, 
apparently bi-concave; anal aperture on the ventral surface 
