OCR Text |
Show 1879.] THE COREAN AND JAPANESE SEAS. 27 HYASTENUS (CHORILIA) JAPONICUS, n. sp. (Plate I. fig. 2.) Carapace triangular, rounded behind, with the regions separated by well-marked depressions, and covered with small 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 carapace, 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, denticulated 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 successively 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 fingers nearly straight, without a hiatus aud strong tooth at base. The nearest ally of this species is unquestionably the C. longipes 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 be 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 including those species of Hyastenus in which the carapace is tuber-culated and uneven above-e.g., the present species, Chorilia longipes, and 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 tuberculated or spinose carapace |