CAMBARUS. 83 
typical form of C. pellucidus, resembling in this respect the form C- pellucidus 
terms. The terminal segment of the telson narrows at the hinder end more 
than in C. pellucidus. 1 do not find the differences in the mandibles, antennal 
scales, and chele mentioned by Packard. 
33. Cambarus Jordani. 
Plate Ill. fig. 3. 
Cambarus Jordani, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 119, 1884. 
Male, form H.— Rostrum broad, subplane, sides nearly parallel, acumen 
long, with minute lateral teeth at base. Post-orbital ridges provided with 
sharp anterior spines. Carapace punctate (sparsely so on the gastric region), 
slightly granulated on the sides. A single acute spine on each side of the 
carapace behind the cervical groove, and a branchiostegian spine on the 
anterior border. Sub-orbital angle prominent. Areola long, narrow, widen- 
ing gradually anteriorly, suddenly posteriorly, smooth, with but few puncta 
irregularly disposed in its field. Abdomen longer than the cephalothorax ; 
proximal segment of the telson bispinous, distal segment rounded posteriorly. 
Kpistoma triangular. Antenne equal in length to the body minus the telson, 
scale broad, greatest width toward the distal end, which is sub-truncate 
and furnished with a sharp external spine. Third pair of maxillipeds hairy 
within. Chela punctate, ciliate; inner margin of hand short, serrate; 
fingers long, costate, outer border of movable one serrato-tuberculate. Car- 
pus with a strong, acute median spine, and a small basal spine on inner 
border; a small spine at each articulation with the chela. Meros smooth 
on the external surface, two ante-apical spines obliquely placed on the upper 
edge. First pair of abdominal appendages short, thick, articulated near the 
base, terminating in two blunt, recurved teeth. 
Length of body, 47 mm.; of carapace, 25 mm.; of abdomen, 24 mm. ; 
of rostrum, 6 mm.; of acumen of rostrum, 2mm. From point of rostrum 
to cervical groove, 15 mm.; from cervical groove to hind margin of cara- 
pace, 8mm. Width of areola, 1.3 mm. Length of antennx, 44 mm. 
Of this species I have seen but one specimen, a male of the second form, 
collected by Prof. D.S. Jordan in the Etowah River near Rome, Georgia, 
communicated by Mr. P. R. Uhler, of Baltimore. It has a toothed rostrum 
and first abdominal appendages like C. Barfonii. It is distinguished from 
the other allied species by its flat rostrum and narrow areola. 
