734 THE AMERICAN NATURALIST. [Vor. XXXV. 
the tip) usually ending in three toes, and bearing two to four spurs 
some distance from the tip. A dorsal proboscis behind the corona. 
Trophi or jaws ramate (Fig. 34). (Ovariestwo.) Order BDELLOIDA 
ér. Corona of two nearly circular retractile lobes, transversely placed 
Family PHILODINIDE 
cr. Eyes two 
dr. Eyes on the frontal column or proboscis . . . . Rotifer 
ez. Constructing and dwelling in tubes 39, Æ. mento Anderson 
e2. Not living in tubes 
ft. Antenna very long (one-half to one-third as long as the 
body) ; foot short (one-third body length) ; spurs short and 
DER. s un 40, R. macroceros Gosse (Fig. 28) 
/?. Antenna not remarkably long 
£I. Body very long and slender, white and transparent ; 
foot extraordinarily long (one and one-half times the 
length of the rest of the body) ; toes long and slender 
41, R. neptunius Ehr. (Fig. 29) 
£2. Foot not remarkably long 
hr. Spurs not twice as long as the width of the joint to 
which they are attached. Body transparent or whitish, 
not colored or dark. 
ir. Body whitish, opaque, passing gradually into the 
foot; spurs one and one-half times as long as the 
width of the joint to which they are attached, and 
forming an obtuse angle with each other 
42, R. vulgaris Schrank (Fig. 3°) 
i2. Body thick, suddenly decreasing in size to form 
the foot, which makes up half the entire length of the 
animal ; spurs produced to a longish point at the tip 
43, R. macrurus Schrank 
h2. Spurs at least twice as long as the width of the 
joint to which they are attached. 
the joint to which they are attached, and with a 
constriction one-third of their length from the tip 
44, R. trisecatus Weber (Fig. 31) 
i2. Body slender; foot long, not distinctly marked 
off from the body ; spurs twice as long as the width 
of the joint to which they are attached, slightly 
swollen at base — 45, R. elongatus Weber (Fig: 32) 
i. Body colored — dark brown, usually covered with 
débris ; transverse folds very marked ; spurs almost, 
or quite, three times as long as the width of the joint to 
which they are attached 46, R. tardus Ehr. (Fig-33) 
