CAMBARUS. 109 



length, triangulai", with acute, upturned, brown, horny terminal spine ; mar- 

 ginal spines short, upturned, fusco-corneous. Carapace flattened above, 

 punctate, lightly granulate on the sides, lateral spine small, often obsolete, 

 branchiostegian spine obsolete ; post-orbital ridges terminating anteriorly in 

 a very short spine, which is sometimes obsolete in large specimens; antero- 

 lateral border very slightly angulated behind the antennas ; areola equal in 

 length to the distance from the cervical groove to the base of the rostrum, 

 narrow, irregularly pimctate, sides subparallel for the greater part of its 

 leno-th, divergent at the fore and hind ends. Abdomen a little shorter than 

 the cephalothorax ; posterior border of telson rounded, posterior margin of 

 basal segment bispinose on each side. Basal segment of antennule armed 

 with an interior spine near the apex of lower side. Antenna3 about as long 

 as the body, spine on external margin of second segment small or obso- 

 lete ; scale broad, a trifle longer than the rostrum, widest beyond the middle, 

 thence tapering to the short, acute, horny-tipped, external apical spine. Third 

 maxillipeds hairy within, nearly naked below. Anterior process of epistoma 

 triangular, antero-lateral borders convex, lateral angles prominent, apex 

 usually blunt. Chela large, punctate ; internal border of hand furnished 

 with a double row of low depressed tubercles; fingers ornamented with lines 

 of dots, of moderate length (the movable finger not mucli more than twice 

 the length of internal margin of the hand) ; fingers gaping at the base, not 

 bearded, movable finger incurved, external margin concave, with obsoles- 

 cent tuberculation like that on the inner margin of the hand ; external 

 finger incurved, external margin convex ; inner margins of both fingers 

 furnished with rounded tubercles. Carpus broad, coarsely punctate above, 

 internal median spine small, in some examples obsolescent, inferior median 

 and external spines small or obsolete ; meros smooth on the external face, 

 with two small, obliquely placed superior sub-apical spines, one or both of 

 which may be obsolete, inferior biserial spines usually but slightly devel- 

 oped, except the apical one of each row. Third segment of third pair of legs 

 hooked. First pair of abdominal appendages, when turned forward, reach 

 the base of second pair of legs ; they are deeply bifid, the rami slender, 

 styliform, shorter than the proximal undivided part; outer ramus straight, 

 or arcuate (the concave side being posterior), subulate; inner ramus a little 

 shorter than outer, straight or arcuate, a little incurved at the apex, tip 

 aciculate, or in old specimens dilated ; a projecting angle or shoulder on 

 the anterior margin at base of the rami. 



