OCR Text |
Show 1877.] CRUSTACEA, CHIEFLY FROM SOUTH AMERICA. 655 the hands are very large, compressed, and slightly cristate ; in the females they are small but compressed. There are eight males and three females in the collection. Length of adult male 1 inch 2 lines, breadth 9 lines. This species, if the determinations of authors are correct, is one of the few that are common to the eastern and western shores of the American continent. It has been recorded by Milne-Edwards, Guerin-Meneviile and v. Martens from the West Indies, by Professor Bell from the Galapagos and Brazil, and by Dana from the coast of Chili. Only a single young specimen from the West Indies is in the collection of the British Museum; but this does not seem to differ specifically from examples from the eastern coast. The original specimen of Petiver was from the West Indies; but his figure is not sufficiently accurate to be available for specific comparison. This species very closely resembles the European A. lunulatus, Risso, but may be distinguished from it by its narrower and less deeply emarginate front, the form of the hands, which are slightly cristate above, and by the shorter, broader, and more dilated penultimate joints of the ambulatory legs. Acanthonyx debilis, Dana, U.S. Expl. Exp. xiii. Crust, i. p. 125, pl. v. fig. 5 (1852), from Valparaiso, differs in the non-cristate wrist and small hands of the males. A. concamerata, Kinahan, Journ. Roy. Dublin Soc. i. p. 334, pl. xiv. fig. 1 (1858), from the North Cinchas Island, Peru, has, if the figure be correct, the anterior lateral angles of the carapace rounded and far less prominent. A. emar-ginatus, M.-Edw. and Lucas, in D'Orbigny, Voy. Amer. Merid. p. 9, pl. v. fig. 2, from Peru, has also the first tooth or antero-lateral lobe far less prominent, the anterior margin of the carapace straight, and the hands more strongly cristate. NEPTUNUS, De Haan. NEPTUNUS ANCEPS. Lupea anceps, De Saussure, Rev. et Mag. Zool. (se'r. 2) ix. p. 502 (1857); M e m . Soc. Phys. et Hist. Nat. Geneve, xiv. (part 2) p. 434, pl. ii. fig. 11 (1858). Neptunus anceps, A. M.-Edw. Nouv. Archiv. Mus. Hist. Nat. x. p. 328 (1861). Hab. Martinique. The length of the single specimen in the collection (a male), is 7 lines, the breadth at base of epibranchial spine 10 lines. The specimen from Martinique differs in some few particulars from De Saussure's description, which was founded upon a very small example. He says that there ten spines upon the antero-lateral margin ; only nine are shown in the figure, including the external orbital spine. In verv young specimens of this genus, however, it is not uncommon to find one or two additional spines upon the antero-lateral margins. There is, according to De Saussure, a second spine at the distal extremity of the superior margin of the hand |