Earring (& Myers—Rotifer Fauna of Wisconsin — II. 533 
marked dorsally with strong, longitudinal folds, gradually dis¬ 
appearing on the sides. The foot is fairly long and wrinkled, but 
not jointed. The two toes are somewhat obtusely pointed, slightly 
decurved and laterally compressed; their length is about one tenth 
of the total length. 
The tubular dorsal antenna is on the abdomen, immediately be¬ 
hind the transverse fold, and joined to the integument in its en¬ 
tire length. The lateral antennae are small, rounded, knoblike, 
setigerous papillae just above and in front of the tail. 
The corona is perhaps easier to understand if it is considered as 
a simplified or specialized Eosphora-QomnsL. As explained under 
this genus, its corona consists of a circumapical band of cilia, in¬ 
terrupted dorsally, with a lateral arc of very long cilia for pro¬ 
pulsion, and an inner arc of fairly long cilia joined to the circum¬ 
apical band at both ends. In Sphyrias the dorsal gap in the corona 
is almost equal to the width of the head, and all that remains of 
the circumapical band is the lateral, auricle-like arc of long cilia ; 
in front of this is a short arc of fairly long cilia, representing the 
inner arc of Eosphora. Nothing remains of the latero-ventral arc 
of the circumapical band normally joining the auricles and passing 
below the mouth except a few short cilia at the sides of the ver¬ 
tical, slitlike mouth. The mouth regio^ is retracted when the ani¬ 
mal swims, and the inner arc of cilia thus forced out even with 
the external or posterior arc; this produces an appearance recall¬ 
ing the form of the hammerhead shark {Sphyrna, in Kafinesque’s 
Greek!). At the point of attachment of the dorsal longitudinal 
muscles are four small tufts of sensory setae. 
The mastax is virgate, but adapted also to prehension. The ful¬ 
crum is very long and straight; it is formed of two plates joined 
together at the edges and forming a Y-shaped trough with the 
apex dorsal. The rami are symmetrical and roughly triangular; 
their inner edges are armed with about twenty long, needle-like 
teeth. The unci have only a single, long tooth, clubbed at the tip 
and with a minute basal plate. The manubria are long, rodlike 
and nearly straight; they diverge from the incus at an angle of 
nearly 45 degrees. Two straight rods, expanded at their dorsal 
ends into triangular plates, are imbedded in the walls of the 
mastax below the dorsal branch of the rami and aid in the support 
of the mastax during the pumping action. The piston is large 
and powerful; its striate longitudinal muscles are very conspicuous. 
