ORTMANN : THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 403 
Point of acumen short. Postorbital ridges short, terminated bluntly in front, 
slightly divergent posteriorly, ending in a low, indistinct swelling. 
Surface of carapace punctate, slightly granulate on the hepatic region, and with 
a few granules on the branchial region, immediately behind the cervical groove. 
No lateral spine. External orbital angle present, distinct, angular or rounded, but 
without tubercle or spine. Branchiostegal spine formed by a small, often indistinct, 
tubercle. 
Abdomen about as long as the carapace, or very slightly shorter or longer, nar- 
rower than the carapace in the male, markedly wider and about as wide as the 
carapace in the female. Anterior section of telson with 1-3 (generally 2) spines on 
the posterior lateral corners. Posterior section semi-elliptical, slightly wider than 
long, and about as long as the anterior section. 
Epistoma similar to that of C. carolinus and monongalensis, comparatively long 
and narrow, rather flat, and with the anterior section semi-circular, semi-elliptical, 
or truncate and subquadrate, with or without median point, and about as long as 
wide. 
Antennula with a small tubercle on the lower margin of the basal joint. 
Antennal peduncle without spines or tubercles on the proximal joints. 
Antennal scale small and short, slightly longer than the rostrum, and reaching to 
the base of the fifth joint of the peduncle of the antenna. Spine of outer margin 
strong; laminar portion not much wider than the spine, its inner margin parallel to 
the outer margin of the spine for a considerable distance. 
Flagellum short, often only as long as the carapace or even shorter, never reach- 
ing beyond the second abdominal segment. 
First pereiopods (Pl. XL, Fig. 6) stout and very robust in old individuals; not 
much different in the male and female, except for their very large size in old males. 
Hand ovate, broad, depressed. Surface punctate. Inner margin of palm convex, 
with two irregular rows of tubercles, and a few scattered tubercles on the upper 
surface near the marginal rows. Outer margin smooth, rounded proximally, 
slightly angular distally. Fingers at least one and one-half times as long as palm 
(the latter measured from articular tubercle with carpopodite to articular tubercle 
with dactylopodite), gaping at the base, straight both in young and old specimens. 
Cutting edges with a number of strong but irregular tubercles; one tubercle at 
about the middle of the edge of each finger is generally the largest. Outer margin 
of moyable finger with more or less distinct tubercles at the proximal end. Upper 
surface of each finger with a low longitudinal rib, bordered by rows of punctures. 
Carpopodite about as long as wide, shorter than palm, with a deep longitudinal 
