754 THE AMERICAN NATURALIST. [Vor. XXXV. 
di. Toes two 
ez. Lorica subcircular or broadly ovoid, with a wide and deep 
lateral furrow. Cathypna 
ft. Lorica rather ftoi, ‘dorsal and yeiai pisti nearly 
equal in size, broadly oval in outline ; toes two-fifths as long 
as the lorica, each with a distinct ange or shoulder at the 
side, near the tip, and with a small sharp claw, which con- 
tinues the inner side of the toe 202, C. Zuna Ehr. (Fig. 141) 
J?. Lorica ovoid, the dorsal plate ending behind in a sub- 
square plate with its posterior lateral corners extended into 
distinct angles. Toes rod-shaped, very long (almost as 
long as the lorica). . 203, C. /eontina Turner (Fig. 142) 
J3- Very large (.31 mm. in length); lorica long ovoid or 
truncate elliptical in form ; dorsal plate projecting pos- 
teriorly as a semicircular plate over the foot. Toes about 
half the length of the lorica . . 4, C. ungulata Gosse 
£2. Lorica longer, usually a ve ris aed in front ; lateral 
furrow not pronounced . Distyla 
Jt. Dorsal plate lacini: £e, iid off into polygoni 
are 
s 
gI. Dorsal plate ending behind in a quadrangular projec- 
tion with may pita sides 
205, D. ohioensis Herrick (Fig. 143) 
£2. Dorsal plate ending behind in two sharp points sepa- 
rated by a broad gap . 206, D. stokesii Pell (Fig. 144) 
£3. Dorsal plate ending behind in a single sharp point 
207, D. ludwigii Eckstein (Fig. 145) 
£4. Dorsal plate not ending behind in projections, but 
bearing in the posterior lateral region two short project- 
ing teeth, protecting two lateral antennz. Foot conspic- 
uous, three-jointed 208, D. spinifera Western (Fig. 146) 
f2. Dorsal and ventral plates marked with small crescentic 
elevations arranged in somewhat regular patterns. Lorica 
of truncate elliptical form, without posterior projections 
209, D. signifera Jennings (Fig. 147) 
J3- Lorica flexible, smooth, or marked with irregular ar wrin- 
kles or longitudinal folds 
£I. Small, lorica parallel-sided, soft, with irregular wrin- 
kles and longitudinal folds . . 210, D. flexilis Gosse 
£2. Lorica long, flexible, nearly parallel-sided when 
extended (Fig. 148); when completely retracted broader 
in front and ending in two strong incurved points (Fig. 
149). Dorsal surface with a few irregular long itudinal 
folds . 211, D. gzssensis Eckstein (Figs. 148 - 149) 
