Earring & Myers—Rotifer Fauna of Wisconsin — II. 517 
wrinkled. The toe is single^ slender and conical, slightly reduced 
at the base and apparently formed by the fusion of the two normal 
toes, as there are two well developed mucus glands; its length is 
one twentieth of the total length. 
There are two dorsal antennae, slightly elevated papillae with 
a minute tuft of sensory setae; they are on the posterior part of 
the head and about 15/i, apart. The lateral antennae are in the 
normal position and very small. 
The corona consists of a circumapical band of moderately long 
cilia; laterally there are two tufts of long cilia, resembling auricles. 
The buccal field is evenly and somewhat sparsely ciliated; on its 
upper edge there is a median tuft of long cilia or setae. The mouth 
is near the ventral edge. Near the lateral margins of the apical 
plate are two unciliated retractile elevations without any very 
definite form; they are constantly being thrust out and withdrawn, 
thus resembling the enigmatic lateral humps; when fully extended, 
they appear to be bluntly conical. 
The mastax is a highly specialized form of the virgate type; all 
the normal elements are firmly fused into a roughly dome-shaped 
structure. The outlines of the incus are still recognizable: a very 
slender, rodshaped fulcrum and two elongate triangular rami, sep¬ 
arated by an elongate oval space. The mallei are no longer di¬ 
visible in unci and manubria; a single, roughly semicircular lamella 
with a posterior, rodlike extension representing the posterior part 
of the median cell, is all that is actually present, and the ventral 
margin is firmly united to the rami. The animal has not been 
observed while feeding, and the operation of the mastax is un¬ 
known ; the sclerified framework may act simply as a support to 
the walls of a pump, the piston moving in the cavity. The possi¬ 
bility is not excluded that it may serve as the real piston, as in the 
genus Lindia, and produce the vacuum necessary for suction by 
a rocking motion; this would, however, appear to require some 
form of an epipharynx, and no trace of this has been found. 
The oesophagus is long and slender. The stomach and intestine 
are separated by a deep constriction. The gastric glands are re¬ 
placed by a cluster of small rounded bodies of high refractive in¬ 
dex, apparently enclosed in a membranous investment; these highly 
refractive globules are also found floating freely in the body cavity, 
and there is always a cluster in the lateral humps; their nature 
and function are unknown. The bladder is a simple expansion of 
