106 A REVISION OF THE ASTACID^. 



Carapace punctate on both the back and sides ; on the gastric region the 

 punctation is very coarse, assuming the form of reticuhition ; cervical groove 

 sinuate ; no lateral or branchiostegian spines ; anterior lateral margins 

 notched behind the antennaj ; areola broad, heavily punctated. Abdomen 

 about the length of the thorax. Telson long, proximal segment bispinose 

 on each side. Antennas slender, shorter than the body by the length of the 

 telson. Antcnnal scale of moderate Avidth, terminal spine very long, reach- 

 ing beyond the tip of the rostrum. Epistoma triangular. External raax- 

 iilipeds hairy within and below. Chelipeds short, stout ; chelas very large, 

 broad, non-tuberculate, hand convex above and below, punctate, internal 

 margin entire ; fingers short, thick, with lines of ciliated dots. Carpus 

 punctate above, with one internal median spine. Ujiper border of meros 

 with one or two ante-apical spines; the biserial spines below are not devel- 

 oped, except the distal one of each row, and even these are minute. Third 

 segment of third pair of legs hooked. First pair of abdominal appendages 

 reach the base of the second pair of legs. They are deeply bifid, the lami 

 recurved ; the outer ramus is aciculate, the inner is enlarged at base and at 

 tip, and the tip is furthermore grooved in front and rounded off at the end. 



Male, form II. — Hand smaller, fingers gaping at base, external finger 

 ciliated at base within, hook on third segment of third logs very small ; first 

 pair of abdominal appendages articulated near the base, thick, inner and 

 outer parts separated for only a very small distance from apex, compressed 

 from side to side, tips a little recurved, blunt-pointed. 



Female. — Chelas somewhat smaller than in the first form of the male, 

 fingers less widely separated at base, external finger ciliated at base within. 

 Anterior border of annul us ventralis nearly obliterated in the median line, 

 lateral borders raised into prominent tubercles, transverse fossa wide. 



Length of body (male, form I.), 45 mm. Length of carapace, 22.5 mm. 

 Length of areola, 8 mm. Breadth of areola, 2 mm. 



In the largest specimen seen, the dimensions of which are given above, 

 the lateral spines of the rostrum are obsolete, the margins simply notched 

 at base of the acumen ; in the other specimens the lateral rostral spines, 

 though small, are evident ; the antennne in the larger specimens are shorter 

 in proportion to the length of the body. 



Thirty-nine specimens (eighteen males, form I., two males, form II., and 

 nineteen females) were collected by C. L. Herrick, for the U. S. National 

 Museum, in Second Creek, Waterloo, and in Cypress Creek, Lauderdale Co., 

 Ala., October, 1882. 



