OF ARTS AND SCIENCES. 125 



broad, greatest width at the middle, thence tapering to the long spine 

 at apex. Third maxillipeds hairy within and below. Anterior pro- 

 cess of epistoma truncate at apex. Chela broad, depressetl> smooth 

 and punctate below, ciliate-punctate above, margined on the outer 

 ed^e. Inner margin of hand short, with a double row of small ciliated 

 tubercles. Fingers of moderate length, straight, corneous and in- 

 curved at tip, costate and puuctato-ciliate above. Movable finger with 

 outer edge furnished with a double row of ciliated tubercles on basal 

 half. Outer finger hairy below at base of inner side. Carpus tuber- 

 culate above, with a strong and acute internal median spine, and a r 



minute one at the base ; smooth below, with two prominent anterior 

 spines. Third pair of legs hooked. First pair of abdominal appen- 

 dages articulated near the base, long, stout, strongly curved, bifid for 

 a short distance from tip, rami divergent, outer one the longer. 



Female. Annulus ventralis triangular, rounded anteriorly, pos- 

 terior wall with a longitudinal sigmoid fissure. Sternum between 

 fourth pair of legs smooth. 



Length, 61 mm. Antennae, 52 mm. 



Twenty-five specimens of this species were collected for the U. S. <P /n ^^ 



National Museum by Mr. Edward Palmer, in a brook running into '^K^ /A~i^ 



the eastern side of Red Foot Lake, near Idlewild Hotel, Obion Co., >-6a fl\<j' 

 Tenn., May 30, 1882. The lot contains males of the second form, J^ . 



and females. The rostrum, chela?, and antennal scale are similar to ^ ^^ 



those of O. virilis. It differs from that species in its linear shorter ,jp ^iijiio 



areola and male appendages, which are more strongly curved and "^-^iCof f^f) ^^ 

 formed more on the pattern of the same parts in G. immunis. In -'Ij^c^.^^ /^^ "^--^ 

 the latter species, however, these appendages are still more strongly 'A^ ^ -^ 

 curved, the areola is not linear in any part, the rostrum is more deeply -^ r^p — 



excavated, longer, and (usually) toothless, the antennal scale is sub- 

 truncate at the end, and the hand different. Its closest relative is 

 C. Mississippiensis. See description of that species. 



Some of the specimens still show spots of dark color (purplish) on 

 the chela?, carpus, and branchial regions of the carapace. In a few 

 specimens there is a very faint indication of a median carina on the 

 rostrum. 



15. C. Alabamensis, sp. nov. 



Male, form I. Rostrum broad, punctate, sub-excavated above at 

 base, with a broad, rounded, slightly elevated median carina near the 

 tip, sides sub-parallel, punctato-ciliate ; acumen long, triangular, mar- 

 ginal spines slightly developed. Anterior S]iine of post-orbital ridge 



