CAMBARUS. 109 
length, triangular, 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 antennx ; areola equal in 
length to the distance from the cervical groove to the base of the rostrum, 
narrow, irregularly punctate, sides subparallel for the greater part of its 
length, 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. Antenne 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 much 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 spies 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. 
