122 PROCEEDINGS OP THE AMERICAN ACADEMY 



pace subcylindrical, somewhat flattened above, punctate, granulated 

 on the sides ; cervical groove sinuate, no lateral nor branchiostegian 

 spine ; sub-orbital angle rounded ; areola long (much more than one 

 half as long as the distance from the cervical groove to the tip of the 

 rostrum), of moderate width, punctate, widening posteriorly. Abdo- 

 men as long as the cephalo-thorax ; telson rounded behind, basal seg- 

 ment bispinous on each side of the posterior border. Basal segment 

 of antennule with an interior median spine. Second and third segments 

 of antenna? not spiniferous (flagellum of antennas broken off in the 

 specimen examined, probably much shorter than the body). Antennal 

 scale short, of moderate width, terminating in a short, acute spine. 

 Anterior process of epistoma triangular, apex pointed, sides convex. 

 Third maxillipeds bearded within, Chelipeds of moderate length, 

 stout ; chela broad, inflated, coarsely punctate above and below, ex- 

 ternal margin rounded; internal margin of hand with a double row 

 of obsolescent tubercles ; fingers stout, gaping at base, costate, heavily 

 dotted-lined, internal margins furnished with rounded tubercles. Car- 

 pus sparsely punctate, armed with a moderate median and a smaller 

 basal internal spine ; below, there are no spines developed. Meros 

 furnished with two nearly obsolete obliquely-placed tubercles near the 

 distal extremity of superior border, and with a double row of tuber- 

 cles below. Second pair of legs provided with long cilia towards their 

 distal extremity. Third segment of third pair of legs hooked. First 

 pair of abdominal legs long (reaching to base of chelipeds), deeply 

 bifid, rami slender, straight, the outer one a little recurved at the tip, 

 aciculate, the inner one slightly dilated near the tip, blunt pointed ; a 

 projecting angle or shoulder at base of rami on anterior margin. 



Female. Hand small, fingers not gaping, ciliated within ; sternum 

 between fourth pair of legs plane ; annulus ventralis bilaterally sym- 

 metrical, anterior border bituberculate, posterior border unituberculate, 

 transverse fossa deep, recurved at each end. 



Measurements of male, form I. : — Length of body, 49 mm. Length 

 of carapace, 25 mm. Length of rostrum, 6 mm. Length from end 

 of rostrum to cervical groove, 15.5 mm. Length from cervical 

 groove to hind border of carapace, 9.5 mm. Width of areola, 2 mm. • 

 Length of abdomen, 25 mm. Length of chela, 23.5 mm. Length of 

 internal margin of hand, 9.5 mm. Breadth of chela, 11.5 mm. Length 

 of movable finger, 14 mm. 



Two specimens, first form of male and female, in the Museum of 

 Comparative Zoology, from Irondale, Mo. 



This species has the general form of body, rostrum, and chelae of 



