CAMBAEUS. 103 



43. Cambarus Palmeri. 



Plato III. fig. 6, Plate X. figs. 5a, 5 a. 



Cambarus Palmeri, Faxon. Proc. Amer. Acad. Arts and Sri., XX. 124,1884. 



Male, form II. — Rostrum broad, subexcavated. margins nearly paral- 

 lel from base to lateral spines, which are small and sharp ; acumen long. 

 Post-orbital ridge with' sharp anterior spine. Carapace smootb and punc- 

 tate above, granulate on sides, lateral spine of moderate size, anterior lateral 

 border notched just below the sub-orbital angle, which is not prominent. 

 Areola linear for a short distance anterior to the centre, with a small ante- 

 rior and a larger posterior triangular field. The length of the areola is 

 one half the distance from cervical groove to tip of rostrum. Abdomen as 

 long as the cephalothorax. Proximal segment of telson bispinose on each 

 side. Antennae nearly as long as the body. Lamina a trifle longer than 

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

 spine at apex. Third maxillipeds hairy within and below. Anterior process 

 of epistoma truncate at apex. Chela broad, depressed, smooth and punc- 

 tate below, ciliate-punctate above, margined on the outer edge. Inner mar- 

 gin of hand short, with a double row of small ciliated tubercles. Fingers of 

 moderate length, straight, corneous and incurved at tip, costate, punctate, and 

 ciliafe 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 tuberculate above, with a strong and acute internal median 

 spine, and a minute one at the base ; smooth below, with two prominent 

 anterior spines. Third pair of legs hooked. First pair of abdominal ap- 

 pendages 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, posterior 

 wall with a longitudinal sigmoid fissure. Sternum between fourth pair of 

 legs smooth. 



Length, Gl mm. Antenna;, 52 mm. 



Twenty-five specimens of this species were collected for the U. S. Na- 

 tional Museum by Mr. Edward Palmer, in a brook running into the eastern 

 side of Red Foot Lake, near bllewild Hotel, Obion Co., Tenn., May 30, 1882. 

 The lot contains males of the second form and females. The rostrum, chela'. 

 and antennal scale are similar to those of C. viriUs. It differs from that 



