j Earring and Myers—The Rotifers of Wisconsin. 609 
quite constant. It is the most transparent of all the Notommatid 
rotifers. 
The head segment is very small; its width is only one half of 
the greatest width of the body. The neck is nearly the same 
width as the head, long and slender, without clearly defined 
posterior limit. A single anterior transverse fold separates the 
head and neck. The abdomen is oval in outline and gibbous 
dorsally, ending posteriorly in a short, collar-like tail. The foot 
is spindle-shaped and has two joints, the proximal much larger 
than the posterior and with a knob-like dorsal projection bearing 
a few long, deflexed setae. The toes are moderately long, about 
one twelfth of the total length, lanceolate, acutely pointed, and 
slightly decurved. 
The dorsal antenna is a small setigerous papilla in the normal 
position; the lateral antennae are minute tubules with a few very 
long setae. 
The apical plate of the corona is frontal, with a marginal wreath 
of cilia and a lateral, auricle-like tuft of very long cilia; the buc¬ 
cal field is oblique and evenly ciliated. 
The mastax is virgate, but retains a strong resemblance to the 
malleate prototype. The fulcrum is long, slender, and slightly 
tapering with a posterior enlargement for the attachment of the 
muscles. The rami are triangular and form a nearly right angle 
with the fulcrum; on the upper surface of the right ramus there 
are nine short transverse ridges continuing over the inner edge 
as blunt, knob-like teeth, interlocking with eight similar teeth 
on the left ramus. The right uncus has eight, and the left seven, 
straight teeth, resting in the grooves between the transverse 
ridges of the rami; the ventral tooth in each uncus is more 
robust than any of the others and clubbed at the point; the re¬ 
maining teeth gradually decrease in size towards the dorsal, 
marginal tooth, which is linear. The manubria are triangular 
anteriorly, and the median branch curves posteriorly towards the 
ventral side. 
The oesophagus is very long and slender. The gastric glands 
are elongate and pyriform. Stomach and intestine are separated 
by a slight constriction. The ovary is normal and the bladder 
very large. The foot glands are very small and slender, reaching 
only to the middle of the anterior fooot joint. 
39—S. A. L. 
