CAMBARUS. 81 
beneath. Third joint of third pair of legs hooked. Fourth pair of legs with 
a conical tubercle on the first segment. First pair of abdominal appendages 
short, stout, twisted, distal half bent in towards the median line of the body ; 
internal part truncate at apex, with a small spine directed backward and 
outward ; external part longer, ending in a short, recurved, blunt, laterally 
compressed, horny tooth. 
Measurements. — Length of body, 81 mm.; of cephalothorax, 45.5 mm. ; 
of abdomen, 57.5 mm, From tip of rostrum to cervical groove, 27 mm. ; 
from cervical groove to posterior border of carapace, 16 mm. Length of 
rostrum, 11 mm.; of acumen of rostrum, 5 mm.; of antennx, 91 mm.; of 
chela, 36 mm.; of movable finger, 22 mm. Width of base of acumen of ros- 
trum, 3 mm.; of areola, 3 mm.; of chela, 15 mm. 
One specimen, collected by Mr. F. W. Putnam in Green River, near the 
Mammoth Cave, Ky., November 5, 1874. 
This species is very distinct from every other known crayfish. In its 
general appearance it approaches those species included in the group typi- 
fied by C. Barton. The rostrum, however, is more after the fashion of C. rus- 
ticus, but the lateral spines are much larger and stand erect. The impressed 
external finger recalls C. Bartonii, var. robusta. The sexual appendages are 
formed nearly as in C. Bartonii. The development of the antenn is extraor- 
dinary, 
32. Cambarus hamulatus. 
Plate IV. fig. 6, Plate IX. figs. la, la’. 
Orconectes hamulatus, Copp and PacKxarp, Amer. Naturalist, XV. 881, Pl. VII. figs. 1, la, 14, Nov. 1881. 
Cambarus hamulatus, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 145, 1884. 
Male, form II.— Rostrum long, subexcavated, foveolate at base, mar- 
gins moderately raised, converging, lateral spines strong and acute ; acumen 
long, narrow, acute. Post-orbital ridges slightly developed, impressed with- 
out; with prominent acute anterior spines. Carapace subcylindrical, flattened 
above, region posterior to cervical groove long; smooth above, granulated 
on the sides. A sharp spine on each side at the base of the antenne at the 
anterior extremity of the cervical groove, and two or three on each branchial 
region just behind the cervical groove, one of which is prominent, the other 
minute. Areola of moderate width, sparsely punctate, sides parallel. Abdo- 
men longer than the cephalothorax, equal to the cephalothorax in width. 
11 
