1879.] THE COREAN AND JAPANESE SEAS. 27 



Hyastenus (Chorilia) japonicus, n. sp. (Plate I. fi». 2.) 



Carapace triangular, rounded behind, with the regions separated 

 by well-marked depressions, and covered with sreiall distant tubercles; 

 of these there are about eight on the gastric and each branchial region, 

 one or two on the hepatic and genital, and one larger on the intestinal 

 region ; the cardiac region is very convex. There is a spine on the 

 side of each branchial region. The horns of the rostrum are straight, 

 not half as long as the carapace, and more divergent than in C. lon- 

 gipes. On the pterygostomian regions, and on the sides of the cara- 

 pace, there is a series of small tubercles. The anterior legs (in the 

 adult male) are robust, the arm granulated and ridged on its under, 

 inner, and outer sides, granulated above, and with two spines near its 

 proximal extremity on its upper and two or three on its under surface ; 

 wrist granulated and ridged on its upper and outer surface ; palm 

 smooth, compressed, acutely carinated above ; fingers smooth, den- 

 ticulated on their inner margins near their apices, the upper with a 

 strong tooth near its base ; when closed, they have a wide hiatus at 

 base. The ambulatory legs are slender, smooth, diminishing suc- 

 cessively in length from the first to the last ; the terminal joints almost 

 immobile and bent at right angles to the preceding. Length of 

 carapace of an adult male about 1 inch to base of rostrum ; greatest 

 breadth about f inch. 



A good series, including males, females, and young, were collected 

 at a depth of 100 fathoms, in lat. 41° 40' N., long. 141° 10' E. 



The description was taken from an adult male. In the females 

 and younger animals several differences are remarked ; notably, the 

 anterior legs are much slenderer, legs granulated and ridged, the fin- 

 gers nearly straight, without a hiatus aud strong tooth at base. 



The nearest ally of this species is unquestionably the C. langipes 

 of Dana (U.S. Expl. Exp. Crust, i. p. 91, pi. i. fig. 5), from the 

 coast of Oregon. The arrangement of the tubercles is nearly the same; 

 but the one now described differs in its shorter, more divergent rostral 

 spines, the shorter spines upon the basal joint of the antennae, and in 

 the arms never being spinulose along the whole of their upper 

 surface, &c., and must he regarded, at least provisionally, as distinct. 

 There is very little hair on the front and sides of the carapace and 

 rostrum ; and the hands are nearly naked. 



Chorilia scarcely differs generically from Hyastenus, the structure 

 of the orbits and antennal region and the characteristic length of the 

 first pair of ambulatory legs being the same in both. It may be 

 convenient, however, to retain the name as a subgeneric division in- 

 cluding those species of Hyastenus in which the carapace is tuber- 

 culated and uneven above — e.g., the present species, Chorilia longi~ 

 pes, aud the Hyastenus oryx and verrucosipes of White. 



Doclea. 



The genera Libinia, Libidoclea and Doclea constitute, in Dana's 

 arrangement, a natural group, characterized by their very convex and 

 orbiculate or shortly pyriform and tuierculated or spinose carapace 



