ORTMANN: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 359 
Body not very robust, not pubescent, with only a few, scattered, short hairs, 
chiefly on the chele, but the hair wears off very soon, and the body becomes smooth, 
with exception of a slight pubescence at the base of the cutting edges of the fingers. 
Carapace suboyate, depressed. Relation G: H: B=1:1:1.2o0r 1.5. (The width 
of the branchial regions appears slightly less than in C. limosus, but this is probably 
due to the fact that the specimens of C. propinquus at hand are rather small). 
Greatest width of branchial regions well behind, at about the middle of the bran- 
chial regions. Carapace flattened dorsally. 
Cervical groove deep, more or less distinctly interrupted on the sides just above 
the lateral spine. Posterior section of carapace about half as long as anterior (rela- 
tion a:p = 1:0.42 to 0.62. 
Areola rather broad, w:] = 1:4.7 to 6.0, with about four irregular rows of 
punctures. 
Rostrum long and broad, reaching to the middle of the fifth joint of the peduncle 
of the antenna, and to the end of the peduncle of the antennula, sometimes slightly 
shorter. Surface concave, with a more or less distinct, low, longitudinal median 
keel toward the tip. Margins elevated, but not much thickened, straight, more or 
less convergent toward the marginal spines. Marginal spines generally well devel- 
oped in young specimens, less so in older ones, sometimes quite small. Acumen 
long, triangular, comparatively longer in young specimens, pointed, about one-third 
as long as the whole rostrum, or shorter. Postorbital ridges slightly divergent pos- 
teriorly, ending anteriorly in a more or less distinct small spine. 
Surface of carapace finely punctate, and slightly granulate on the hepatic regions 
in old specimens. Sides with only one spine on the branchial regions, immediately 
behind the cervical groove. This spine is always present and sharp, but generally not 
very Jarge. No other spines on the sides of the carapace. External orbital angle not 
marked. Branchiostegai spine small, but sharp, or tuberculiform, or even obsolete. 
Abdomen longer than carapace, slightly narrower than the carapace in the male, 
about as wide as the latter in the female. Anterior section of telson on the outer 
posterior corners with one to three spines (two spines is the general condition). 
Posterior section of telson semielliptical, considerably wider than long, and slightly 
shorter than anterior section, 
Ypistoma with posterior part short and broad, almost three times as wide as long, 
not plane, with a transverse groove and an anterior median depression running into 
vach other. Anterior section constricted at base, its anterior margin generally almost 
semicircular, with a median point and an indistinct angle on each side, but shape 
rather variable: sometimes it is truncate anteriorly, with or without median point, 
