CAMBARUS. 25 
of epistoma broadly triangular. Antenne shorter than the body. Antennal 
scale a little shorter than the peduncle, equal to the rostrum, broad, broadest 
at the middle. Chelipeds slender, chela long, inner and outer margins par- 
allel, squamoso-tuberculate, tubercles ciliate, those along the inner margin of 
the hand blunt spiniform. Fingers longer than the hand. Opposed margins 
of fingers ciliate, with one or two small spinous teeth. Carpus long triangu- 
lar, smooth without, tuberculate and spinous within. Meros with scattered 
impressed dots without, tuberculate on the upper margin; one or two spines 
at the anterior end of upper margin, two rows of spines beneath. Third and 
fourth pairs of legs hooked on third segment. Anterior abdominal legs of 
moderate length, deeply excavated on the outer side near the tip; a beard- 
like tuft of cilia from the protuberance behind the excavation ; the tip bears 
three flattened horny teeth; inner part ciliate, with a long spine directed 
outwards and forwards. 
The second form of the male has shorter chelipeds, smaller hooks on the 
second and third pairs of legs, the terminal teeth of the first pair of ab- 
dominal legs smaller and not corneous. 
In the female the chelipeds are short, the chelee broad. Sternum bitu- 
berculate between the fourth pair of legs. Annulus ventralis umbilicoid, 
with a tubercle in the median depression. 
Length, 100 mm. Rostrum, 15 mm.; acumen, 53 mm. Length of cara- 
pace, 51mm. From cervical groove to posterior margin of carapace, 18.5 
mm. Abdomen, 50 mm. Width of areola, 1.5 mm, Chelipeds, 92 mm. 
Chela, 43 mm. 
Known Localities. — Mississippi: Macon, Artesia. 
Closely related to Cambarus Blindingii, but easily distinguished by the 
first pair of abdominal legs of the male, which are characteristic even in very 
small specimens. Over a dozen specimens of this species (including males 
of the first form, males of the second form with first pair of abdominal 
appendages articulated near the base, and unarticulated, and females) were 
collected by Prof. O. P. Hay in Eastern Mississippi. One lot has a particular 
locality specified, — Macon. Macon is situated on the Noxubee, an affluent 
of the Tombigbee River. Another lot was collected at Artesia, a town about 
twenty miles north of Macon. 
