Harring and Myers—The Rotifers of Wisconsin. 631 
and tapering for one half their length, ending in very slender, 
acute points. 
The dorsal antenna is double; two fairly large, conical tubules, 
ending in a rounded knob with a tuft of long sensory setae, pro¬ 
ject from the dorsal surface of the head; their distance apart is 
about one half the width of the head and they are united by a 
conspicuous muscular band, as in Asplamchna. The lateral an¬ 
tennae are very far back on the body, near the base of the tail; 
they are very long, tubular, knobbed at the ends, and carry a 
few excessively long setae. 
The corona is oblique, and its length is a little more than one 
fifth of the total length. It has a median, trough-like depres¬ 
sion throughout its entire length, and the post-oral portion pro¬ 
jects as a fairly prominent chin. No auricles are present; at the 
anterior lateral angles are two V-shaped, concave, ciliated ap¬ 
pendages of the corona, which may be rudiments of auricles. The 
ciliation of the corona is very faint and may serve only to con¬ 
vey food to the mouth; at least it appears to be entirely too feeble 
to be of any use in locomotion. 
The structure of the mastax is peculiar and very aberrant. 
While it is of the pumping type, it has noting else in common 
with the normal form of the virgate mastax. Its correct inter¬ 
pretation is still a matter of doubt, and the affinities of the genus 
are therefore unknown; there is a certain resemblance to the 
mastax of the genus Lindia, but it does not extend beyond gene¬ 
ralities. In spite of long continued efforts, the animal has never 
been observed while feeding, and it appears to be necessary to 
await some fortunte accident to elucidate fully the action of the 
mastax. 
The fulcrum is a very small, thin lamella. The rami at first 
sight resemble the forcipate type, but instead of being straight 
they are curved nearly in a semicircle and enlarged by a broad, 
thin lamella attached to the external edges. At the mouth there 
are two large, blunt, conical teeth which appear in lateral view 
as superposed knobs. The alulae are large. The uncus has only 
a single long and slender tooth, resting with its tip on the ramus 
immediately below the toothlike projection; the basal plate of the 
uncus is represented by a crescent-shaped, extremely thin lamella. 
The manubrium is a curved rod with two anterior and two poste¬ 
rior lamellar, small apophyses. In addition to the incus and 
