736 THE AMERICAN NATURALIST. [Vor. XXXV. 
i2. Each jaw (Fig. 42) with one large and two 
small teeth ; spurs (Fig. 43) scarcely as long as 
the width of the joint to which they are attached, 
swollen at base ; body yellowish 
57, C. musculosa Milne (Figs. 42 and 43) 
£2. Foot ending in a disk in place of toes ; teeth, six to 
eight in each jaw; body reddish . 58, C. magna Plate 
é2. Corona a flat surface covered with cilia, on the ventral side of the 
axierent (Fig.4dM) ^. Ius c 2 E 
cz. Skin smooth; no eyes; proboscis without bristles and with a 
few cilia ; body broad . « 59, A. vaga Davis (Fig. 44) 
42. Swimming with the corona ; not creeping like a leech (sometimes 
creeping with the toes). Jaws of various forms, but never ramate. 
A very large number of rotifers fall within this division, and the recogni- 
tion of species, or in many cases even of genera, is very difficult. In order 
to reduce the difficulties to a minimum, I separate out a number of species 
having striking peculiarities, by means of the first five subdivisions given 
below (47-45). The following is to be especially noted ; only the species 
mentioned under a given characteristic possess that characteristic. For 
example, any species having swimming appendages will be found under 45, 
species not named under this subdivision do not have such appendages. 
br. Spherical in form ; no foot ; ciliary wreath midway between the 
equator and one pole of the sphere 
60, Trochosphera solstitialis Thorpe 
62. Foot ending in a single pointed “ toe” 
cr. Corona a circle of strong cilia ; mouth in the center ; form of 
the body conical; one eye 61, Microcodon clavus Ehr. (Fig. 45) 
c2. Corona an oblique ciliated disk, with two auricles; body 
brownish red or cherry red in color; one eye 
62, Notommata monopus Jennings (Fig. 46) 
c3. Corona an oblique ciliated surface with weak cilia; no eye: 
parasitic in fresh-water annelids . 63, Albertia naidis Bousfield 
63. Foot ending in two pointed projections, not side by side (as in 
most rotifers), but one dorsal, the other ventral. Otherwise much 
like No. 61 
64, Microcodides chlena Gosse (orbiculodiscus Thorpe) 
64. Corona extended dorsally into a large and broad proboscis, fringed 
with cilia and bearing near its end two red eyes 
65, Rhinops vitrea Hudson (Fig. 47) 
65. Body bearing swimming or skipping appendages, in the form 
movable spines, blades, or branching crustacean-like limbs ; no foot 
cr. Six branching appendages, somewhat like those of a crusta- 
cean ; two small stylate appendages on the posterior dorsal 
surface. Eyes two . . 66, Pedalion mirum Hudson (F ig. 48) 
c2. Twelve blade-shaped appendages, with serrate edges, arrang 
