THE SPIDER CRABS OF AMERICA 221 



ROCHINIA VESICULARIS (Rathbun) 



Plate 230 



Scyramathia vesicularis Rathbun, Mem. Mus. Comp. Zool., vol. 35, 1907, 

 p. 73, pi. 5, fig. 7; pi. 8, figs. 1 and la (type-localitj', SE. of Hood Island, 

 Galapagos Islands, 300 fathoms; (holotype, Cat. No. 32860, U.S.N. M.). 



Diagnosis. — Median spines 4; gastric spines 4; dorsal and marginal 

 spines short and numerous; 2 spines on basal antennal article; a spine 

 on lower margin of orbit outside the antennal article; none at buccal 

 angle; a spine or sharp tooth at end of merus of all legs. 



Description. — Body and legs evervAvhere covered with a pubescence 

 formed of spherical vesicles; a few long, slender hairs on the gastric 

 region, the lateral margins and the rostrum. Carapace behind the 

 orbits armed A\'ith 20 short, stout, sharp-pointed spines, of which 4 

 are gastric (2 median, the lateral spines on either side of the anterior 

 median), 1 cardiac, 1 intestinal, 1 hepatic, marginal (paired), 6 

 branchial (paired), of which one is suberect above the lateral angle, 

 one is almost in line "with the latter and the cardiac spine, 2 others, 

 more anterior, form a straight line with the cardiac spine, while 2, 

 smallest are above the bases of the second and tliird legs. Pre- 

 ocular spine similar to the others; postocular cup narrow, curved 

 inward, spine-tipped. Rostrum composed of 2 slender, moderately 

 divergent horns, two-fifths the length of the remainder of the cara- 

 pace. Basal antennal article armed \vith two spines on its outer 

 margin; immediately behind the posterior of these is another spine on 

 the orbital margin. 



Chelipeds of small male just as long as carapace and rostiTim and 

 a little stouter than the legs; arm mth a row of four short spines above, 

 which increase toward the wrist; wrist with 3 or 4 similar spines; 

 palm vrith. sides parallel, one and one-half times as long as fingers, 

 which meet when closed, edges crenulate. Merus of ambulatory 

 legs ^^^th a spine or sharp tooth at distal end; first pair one and one- 

 half times as long as carapace and rostrum. 



In the female the rostrum is shorter, one-third the length of re- 

 mainder of carapace; the cheliped equals length of carapace and half 

 the rostrum; fingers relatively longer than in the male; first ambu- 

 latory one and one-fifth times as long as carapace and rostrum. 



Measurements. — Male holotype, total length of carapace 20.7, 

 width 11.5, length of rostral horns 6 mm. 



Range. — Off the Galapagos Islands; 300 fathoms. 



Material examined.- — Southeast of Hood Island, Galapagos Islands; 

 lat. 1° 30' 30" S.; long. 89° 35' 00" W.; 300 fathoms; brk. Sh. Glob.; 

 temp. 48.6° F.; November 7, 1904; station 4642, Albatross; 1 male, 

 holotype, 2 females (32860). 



