Harring & Myers—Rotifer Fauna of Wisconsin — II. 531 
ciliated; the buccal field is covered with very short, close-set cilia 
and has a median depression around the mouth. The marginal 
cilia are short except on two laterally projecting, auricle-like areas. 
The dorsal and lateral antennae are small setigerous papillae in 
the normal positions. 
The mastax is virgate and slightly asymmetric. The fulcrum is 
long and broad at the base, tapering gradually to the slightly in¬ 
curved posterior end. The rami are roughly triangular and have 
moderately large alulae. There is a heartshaped opening just 
above the fulcrum; this is followed in the right ramus by four 
small teeth, two strong, apical teeth and two small teeth on the 
dorsal portion; the left ramus has five small teeth above the ven¬ 
tral opening and one large, apical tooth, followed by two small 
dorsal teeth. The rami are prolonged dorsally by two thin, blade¬ 
like curved pieces, not observed in the mastax of any other Notom- 
matid. The unci have a single, large tooth with two small acces¬ 
sory teeth attached to the clubbed tip on the ventral side; the 
basal plate is irregularly oval and has a narrow, denticulate por¬ 
tion adjoining the tooth on the dorsal side. The basal plate of the 
manubria is large; the posterior branch is nearly straight and has 
a slight terminal expansion. Two slender, double-curved rods are 
imbedded in the walls of the mastax just below the posterior edges 
of the rami; they serve as supports during the pumping action. 
The piston is large and muscular. On the left side is a granular 
area which appears to represent an atrophied salivary gland. 
The oesophagus is very long and slender. There is no constric¬ 
tion between the stomach and intestine. The gastric glands and 
ovary are normal. The cloaca functions as a bladder. The foot 
glands are pyriform and very small. 
The ganglion is large and saccate. The retrocerebral organ con¬ 
sists of a very small, pyriform sac and two short subserebral glands, 
which contain a rounded mass of bacteroids at the level of the eye- 
spot. There are two accessory frontal eyespots on the apical plate 
in addition to the cervical eyespot at the posterior end of the 
ganglion. 
Total length 250-300ju,; toes 18-22jtA; trophi 38/x. 
Eothinia argus was collected in small numbers in Lenape Lake, 
at Mays Landing, New Jersey. It is very closely related to 
E. triphaea, but is readily distinguished by the much shorter toes 
and the long retrocerebral sac. 
