Harring and Myers—The Rotifers of Wisconsin. 571 
The mastax is of the normal virgate type, with decidedly asym¬ 
metric trophi, much more robust on the left side than on the 
right. The fulcrum is long and stout, nearly parallel-sided for 
two thirds of its length, and from there tapering to the slightly 
incurved point, this terminal portion having a Y-shaped cross 
section, giving additional surface for attachment of the muscles of 
the piston. The rami are nearly semicircular in a ventral view, 
and are bent nearly at a right angle at the extreme anterior point. 
The right ramus has a moderately deep, ventral transverse groove, 
in front of which there is a broad, lamellar tooth, projecting 
diagonally towards the left; the margin of this tooth is coarsely 
denticulate. The left ramus is excavate opposite this tooth; 
posteriorly the alula is continued as a stout, incurved spur. The 
left uncus has one very large, club-shaped ventral tooth; there 
are three additional rudimentary teeth radiating fanwise from 
the basal plate of the uncus. The right uncus has two well de¬ 
veloped teeth, the ventral one much larger than the second, but 
itself only half the bulk of the left tooth; these are followed by two 
small, pointed teeth and a blunt, blade-like dorsal tooth, the basal 
plate uniting all nearly to the tips. The manubria are very 
robust; the median section is very broad and nearly parallel¬ 
sided, slightly incurved posteriorly and expanded into a roughly 
triangular plate at the anterior end. The oesophagus is long and 
slender. The gastric glands, stomach-intestine, and ovary are 
normal; the bladder is formed by an expansion cf the cloaca, as 
in Notommata pseudo cerberus and in a few other species. Two 
long, slightly club-shaped foot glands are present. 
The retrocerebral organ consists of an extremely long, clear, 
vacuolate sac, one third the length of the body, and two very 
short subcerebral glands, which usually include bacteroids, but 
not in great numbers. The eye-spot is at the posterior end of 
the small, saccate ganglion. 
Total length 500-550/a; toes 30-33/a; trophi 75/a. 
Notommata falcinella was collected some years ago in great 
numbers among submerged sphagnum at the head of Furnace 
Creek, near Baltimore, Maryland, in company with Notommata 
saccigera. It has never been found since, although the same spot 
has been searched every year at the same season. 
This species is closely related to the other large species of the 
genus, but is readily distinguishable by the small spur at the base 
of the toes. 
