Page 689

Harring & Myers-Rotifer Fauna of Wisconsin.-IV. 689
Iy emptying
! slender, cy-
I its contents
bnder and so
)osterior end
Xarly as long
posteriorly,
The cervical
-he openings
toes 9-10,A;
y placed at
hio collected
records this
isbourg and
g's Diglena
ision of the
ly justified.
s may refer
is not now
bous poste-
)f the total
the outline
Aotic zoo-
tual width,
ell marked
Ms gradual-
;in young
  The tail
  foot is
h, slightly
onical and
the total
The dorsal antenna is a small, setigerous pit in the normal
position; the lateral antennae are tubular, with a small tuf t
of sensory setae.
The corona extends down on the ventral side about one
third of the length of the body; the post-oral portion pro-
jects from the body as a rudimentary chin. The auricles
are rather small and the ciliation continuous with the cor-
ona.
The mastax is virgate, but the pumping action is lost.
The trophi are asymmetric and robust. The rami are ly-
rate, broad and strongly divergent at the base, continuing
as parallel, rather slender rods of irregularly triangular
cross section, abruptly bent inward and knobbed at the
tip, which is armed with five or six long, acutely pointed
and slightly divergent teeth. The basal apophysis, which
is nearly always present in the Notommatinae, is preserved
as a broad rounded elevation on the ventral surface of the
rami. On the dorsal side there is a remnant of the triangu-
lar, lamellar extension of the rami in I. aurita, similar in
form, but smaller; the oral combs are also present in this
species. On the inner margin of the left ramus is a thin,
narrow lamella nearly as long as the ramus itself, on the
right a broad, finely striated, denticulate lamella, continu-
ing from the base to the terminal, toothed knob. The
alulae are large, pointed and decurved, with a lamellar
extension continuing nearly to the tips, the right much
broader than the left. The fulcrum is as long as the rami,
broad at the base, reduced in the middle and expanded
posteriorly. The unci are long, stout, slightly curved and
acutely pointed; near mid-length is a knoblike enlargement
resting on the rami and serving as a hinge; to it is attached
a large secondary tooth, diverging slightly from the main
tooth. The manubria are as long as the incus, nearly
straight, broadly expanded anteriorly and abruptly curved
posteriorly. The mastax is not protrusible through the
mouth.
  Gastric glands are absent. The stomach has anteriorly
two blind, fingerlike caeca, extending forward on the sides
of the mastax almost to the ganglion; there is no distinct
separation between stomach and intestine. A bladder is
not present, the lateral canals emptying directly into the
44
r Letters.
A
I ,4q