82 A REVISION OF THE ASTACID.E. 



Telson long, proximal segment bispinose on each side, distal segment ellipti- 

 cal. Anterior process of epistoma obtusely subtriangular. Eyes rudimentary, 

 concealed under the rostrum. Basal segment of antennules furnished with 

 a sharp spine beneath near the distal extremity. Antennae shorter than the 

 body, scale equal to the rostrum in length, broad, broadest at the distal end. 

 external border slightly convex, inflated, produced into a long, acute spine. 

 Third pair of maxillipeds bearded within. Chelipeds slender, chela long. 

 slender, subcylindrical, slightly pubescent, inner margin straight, subdentate. 

 Fingers long, slender, subcostate, inner margin straight, hairy. Carpus long, 

 inner side tuberculate, with a sharp anterior spine ; two spines on the ante 

 rior margin of the lower surface. Upper margin of the meros granulated, 

 with two sharp spines near the distal end ; lower surface of the meros fur- 

 nished with sharp spinules arranged biserially. Third pair of legs hooked. 

 First pair of abdominal appendages fashioned after the type of the C. Bar- 

 torrii group, articulated near the base, short, dilated in the middle, tip bifid, 

 recurved ; inner and outer parts forming recurved hooks, the tip of the inner 

 attenuated ; outer part double within. The curve of the terminal hooks is 

 not so strong as in C. Bariortii and allied species, and the two are closely 

 approximated instead of being separated. 



Female. — Body stouter, sternum between the fourth pair of legs smooth, 

 annulus ventralis broad, with a raised rim on the posterior margin, and a 

 wide longitudinal sulcus anteriorly. 



Measurements of male, form II. — Length, 44 mm. ; of carapace, 21 mm. ; 

 of rostrum, 5 mm.; of acumen of rostrum, 2.5 mm. From tip of rostrum to 

 cervical groove, 12 mm. ; from cervical groove to posterior border of cara- 

 pace, 9 mm. Length of abdomen, 23 mm. ; of antennae, 35 mm. ; of cheliped, 

 31 mm. ; of chela, 15 mm. Breadth of chela, 3 mm. ; of carapace, 8 mm. 



Locality. — Nickajack Cave, Tennessee. 



I am indebted to Professor Packard for an opportunity to examine four 

 males, form II., and two females of this species, which was discovered by 

 Professor Cope while exploring Nickajack Cave, in the southern part ot 

 Tennessee, near the point where the boundary of that State is met by the 

 line which divides the States of Georgia and Alabama. In general form and 

 appearance it bears a close resemblance to C. pelluddus, but the carapace is 

 less spiny, and the male has hooks on the third pair of legs only, and the 

 first pair of abdominal appendages are formed after the fashion of the C. Bar- 

 torrii group. The rostrum tapers towards the tip more than it does in the 



