Barring and Myers—The Rotifers of Wisconsin. 583 
greatest width of the body, and their length is but little more. 
The single anterior transverse fold is well marked. The abdomen 
increases gradually in width to a point about two thirds the 
length and is rounded posteriorly. A tail is not present. The 
foot has two joints, both short and fairly stout. The toes are 
fairly long, about one seventh of the total length, slender, taper¬ 
ing, outcurved and decurved. 
The dorsal and lateral antennae are small setigerous papillae 
in the normal positions. 
The corona extends down on the ventral side about one third 
the length of the body; the post-oral portion forms a slight chin. 
The auricles are short and stout, and the ciliation is continuous 
with the corona. 
The mastax is virgate, with slightly asymmetric trophi. The 
fulcrum is long, moderately broad, slightly tapering, and fairly 
stout; the posterior end is slightly expanded and curves inward. 
The rami are approximately triangular in ventral view and are 
bent nearly at a right angle at the extreme anterior point; on 
their inner, ventral edges there is a blunt projection, continuing 
the line of the fulcrum and bifid at the anterior tip; this cor¬ 
responds to the basal apophysis of the mallcate mastax. Behind 
this projection the rami are slightly excavate, and the inner edge 
of the right ramus is concave, while the left ramus is convex; 
both are coarsely denticulate, and the left ramus is also striate. 
The well developed alulae end in curved, horn-like prolongations; 
their tips are only partly sclerified, so that the actual length is 
somewhat uncertain. The unci have a single well developed ven¬ 
tral tooth and a rudimentary second tooth immediately behind 
it; the basal plate is subsquare and crossed by a diagonal rib from 
the base of the ventral tooth to the anterior dorsal angle. The 
right ramus has four short, curved pre-uncial teeth loosely at¬ 
tached to its tips, and the left has five similar, but more slender, 
teeth. Some distance below the posterior edge of the dorsal sec¬ 
tion of the rami, a slender, nearly straight rod is imbedded in 
the walls of the mastax as additional support during the pump¬ 
ing action. The anterior half of the manubrium is a rather nar¬ 
row plate and the posterior a slender rod, curving towards the 
ventral side at the tip. The small, slender, bent rods in front of 
the rami support the edges of the mouth. The oesaphagus is 
short and rather slender. The gastric glands, stomach-intestine, 
