Report on the zoological collections made in the Indo-Pacific Ocean ...

196 COLIECTIONS FEOM MELANESIA.13. Hyastenus (Chorilia) planasius.Pisa planasia, Adams i^" White, Crust, in. Zool. Voy. ' Samarang,'p. 9, pi. ii. figs. 4,5(1848).Hyastenus planasius, A. M.-Edivards, N. Arch. Mus. Hist. Nat. viii.p. 250 (1872).A small male was obtained at Port Denison with H. oryx(No. 122). The original types (and specimens in the Museumcollection) were from the Chinese seas.14. Hyastenus (Chorilia) convexus. (Plate XYIII. fig. B.)Carapace subpyriform, somewhat scantily pubescent ;gastric regionelevated, rounded and convex ; cardiac region also somewhat elevatedand rounded ; branchial regions with three low rounded prominences; no lateral epibranchial spine ; the prseocular angle of theorbit is prominent, but can scarcely be said to be produced in theform of a spine ; there are two spines on the ptcrygostomianregion, between the lateral margins of the buccal cavity and thesides of the carapace. Spines of rostrum slender, nearly straight,and strongly divergent. Postahdominal segments distinct. Easalantennal joint with a small spine or tooth at its antero-externalangle. Chelipedes of male of moderate length ; merus or armrather slender and nearly smooth ; wrist with a very small toothon its inner margin ;palm not twice as long as broad, somewhatinflated, with a small tubercle on its upper margin ; fingers aboutas long as the palm, arcuated, meeting only toward the apices,which are minutely denticulated and acute ; upper finger with atubercle or small tooth on its inner margin near the base ; thefingers (when closed) have between them a wide hiatus. Ambulatorylegs very slender and smooth ; the anterior pair much thelongest, the three following diminishing successively in Jength.The colour of the single specimen examined is a uniform lightyellowish brown. Length of carapace a little over 5 lines (11 mm.) ;greatest breadth nearly 4 lines (8 mm.) ; length of rostral spinea little over 3 lines (7 mm.), of chelipede about 6 lines (nearly13 mm.), of first ambulatory leg rather over 10 lines (22 mm.).The unique male example was obtained at Port Molle, 14 fms.(No. 93), and in size and form of the chelipedes is very comparableto H. gracilirostris, Miers, from the Fijis, from which, however, itis at once distinguished by the absence of spines on the carapace,&c.15. Naxia serpulifera, M.-Edw.Thursday Island. 4-6 fms. (No. 130), two young males (firstcollection). A good series of different ages and of both sexes fromthe same locality has been retained from the second collection (175).Specimens are in the British-Museum collection from Shark Bay,