532 Wisconsin Academy of Sciences, Arts, and Letters. 
Genus SPHYRIAS Harring. 
Notommatid rotifers with short, broad, saccate, illoricate body; 
the head is very broad and truncate anteriorly and has two short, 
stumplike lateral projections; it is separated from the abdomen by 
a well marked constriction; the abdomen is subsquare and ends in 
a collarlike tail; the foot is long and wrinkled; the toes are short, 
conical and obtusely pointed. 
The corona consists of two roughly circular wreaths of long cilia 
at the edges of the short, lateral projections of the head; the 
anterior surface of the head is unciliated; the mouth is near the 
ventral margin and strongly protrusile. 
The mastax is virgate; the rami are roughly triangular and 
strongly curved, the inner margins armed with numerous short, 
closely spaced, needlelike teeth; the fulcrum and manubria are 
long, straight rods; the unci have only a single functional tooth; 
the piston is very large. 
The retrocerebral organ is rudimentary; the two eyespots are 
on the lateral projections of the head. 
Type of the genus.—Sphyrias lofuana CRousselet) = Notops 
lofuana Rousselet. 
SPHYRIAS LOFUANA (Rousselet). 
Plate XLII, figures 1-5. 
Notops lofuana Rousselet, Proe. Zool. Soe. London, 1910, p. 795, pi. 75, 
figs. 1-3. 
Sphyrias lofuana Harking, Bull. 81 U. S. Nat. Mus., 1913, p. 96; Proe. 
U. S. Nat. Mus., vol. 46, 1913, p. 400, pi. 37, figs. 4-8. 
The body of this species is short, stout and truncate anteriorly; 
its greatest width is about one half of the total length. The in¬ 
tegument is moderately flexible and the outline is constantly 
changing in response to the violent contractions of the animal. It 
is a moderately transparent species. 
The head and abdomen are separated by a deep transverse fold. 
The outline of the head is variable; when the animal is at rest (as 
represented in the figures), it is broadly triangular and wider than 
the abdomen; when it is swimming, the mouth region is retracted 
and the head becomes squarely truncate. The abdomen is sub¬ 
square in dorsal view, truncate posteriorly and ends in a short, 
very wide, collar-like tail, surrounding the base of the foot; it is 
