OF ARTS AND SCIENCES. 127 



its broad and short areola from the other species in which the first 

 abdominal appendages are formed after the pattern of those of 0. im- 

 mimis. The section of the carapace behind the cervical groove is 

 very short in this species, and the dense beard at base of the ex- 

 ternal finger is very characteristic. In C compressus the areola, 

 althou'i'h broad, is long, and the strong lateral compression of the 

 body, different form of the chela, &c., distinguish it at a glance from 

 this species. 



16. C. COMPRESSUS, sp. nov. 



Male, form I. Rostrum narrow, excavated, curved downwards, with 

 a longitudinal median carina; margins thickened, converging, with a 

 line of ciliated dots ; acumen long, triangular, with acute lateral spines 

 at base which are obsolescent in the largest specimens. Cephalo- 

 thorax strongly compressed laterally. Post-orbital ridges armed with 

 acute anterior spines. Carapace punctate on both the back and sides ; 

 on the gastric region tlie punctation is very coarse, assuming the form 

 of reticulation ; cervical groove sinuate ; no lateral or branchiostegian 

 spines ; anterior lateral margins notched behind the antennas ; areola 

 broad, heavily punctated. Abdomen about the length of the thorax. 

 Telson long, proximal segment bispinose on each side. Antennae 

 slender, shorter than the body by the length of the telson. Antennal 

 scale of moderate width, terminal spine very long, reaching beyond the 

 tip of the rostrum. E2)lstoma triangular. External maxillipeds 

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

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

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

 Carpus punctate above, with one internal median spine. Upper 

 border of meros with one or two ante-apical spines; the biserial 

 spines below are not developed, except the distal one of eacli 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 rami 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 segement of third legs 

 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. 



