Harring and Myers—The Rotifers of Wisconsin. 615 
tip they are abruptly reduced to needle-like points. Their length 
is about one sixteenth of the total length. 
The dorsal and lateral antennae are small setigerous papillae 
in the normal positions. 
The corona extends down the ventral side for about one fourth 
the length of the body; the post-oral portion projects as a slight 
chin. The auricles are relatively small and carry a tuft of close- 
set, moderately long cilia, not continuous with the corona. 
The mastax differs from the typical form of the genus in the 
absence of an epipharynx, as well as in other minor details. The 
rami are slightly asymmetric and oval in outline, produced later¬ 
ally as thin lamellae; at the anterior angles, where the dorsal pro¬ 
longation branches off, are two large, blunt, projecting teeth on 
each ramus. The fulcrum is rather short, slightly curved, and 
tapering to a small posterior expansion. The unci have each 
two functional teeth; the left uncus has a large, robust ventral 
tooth, slightly clubbed at the tip, which has a decided bend for¬ 
ward; the second tooth is more slender and a little shorter, with 
a similar forward inclination; from its tip two diagonal, slightly 
divergent ribs go to the base of the uncus; the dorsal tooth is 
very slender, almost linear. A plate-like web unites all the teeth 
of the uncus nearly to their tips. Attached to the ventral tooth 
at the point is a short, but fairly large, pre-uncial tooth. The right 
uncus is slightly different from the left; the two principal teeth 
are much more slender, and of the two diagonal ribs starting at 
the tip of the second tooth, the dorsal one is absent on the right 
uncus. The ventral branch of the manubrium is large and of 
very irregular form; its general direction is parallel to the axis 
of the body; the median branch is a slender, slightly curved 
rod, forming an angle of about 45 degrees with the ventral branch 
and united to it by a thin lamella extending well down on both 
branches. The dorsal branch is a slender rod, turning back and 
joining the median branch with its threadlike point; it acts as 
a reinforcement to the dorsal, lamellar extension of the median 
branch of the manubrium. As stated above, no epipharynx is 
present. There appears to be a rudimentary piston. 
The oesophagus is moderately long and slender. The gastric 
glands, stomach-intestine, and ovary are normal; a large bladder 
is present. The foot glands are small and club-shaped. 
The ganglion is small and saccate. The retroeerebral organ 
is limited to a very small, ductless sac at the posterior end of 
