OCR Text |
Show 34 CRUSTACEA. OovronE, Fabr. Eyes extending into the greater part of the length of their pedicles, or claviform; third joint of the external foot-jaws forming a long square; tail of the males very narrow, and the last joint an elongated triangle; that of the females is oval. The claws are nearly similar, strong, but short, and the forceps shaped like a reversed heart. Agreeably to the indication afforded by theit· generic name, these Crustacea run with great swiftness, which indeed is such, that a horse can scarcely overtake them, whence the name of Eques, given to them by the older naturalists. They are now sometimes termed Land-Crabs, and occasionally, naturalists have confounded them with the Gecarcini, under the general denomination of Tourlouroux. The Ocypodes, during the day, remain in the holes or burrows they have excavated in the sand, near the sea-shore, and quit them after sun-set. Ocyph. eques; Cancer cursor, L.; Cancer eques, Bel.; Ocyph. ippeus, Oliv., Voy. dans l'Emp. Ottom., II, xxx, 1. Distinguished from all the others by the bundle of hairs, which terminate the ocular pedicles. It inhabits the coast of Syria, that of Africa bordering on the Mediterranean, and is even found at Cape de Verd. In the Ocyp. cerathophthalmus; Cancer cerathopt., Pall., Spic. Zool., fasc. IX, v, 2-8, the superior extremity of these pedicles ex· tends beyond the eyes for more than a third of their whole length, in a conical and simple point. The forceps are cadiform, very rough, and their cutting edge dentated. From the East Indies. In others the pedicles are terminated by the eyes forming a sort of club. Some from the eastern continent and all those of the western world are thus formed, but the latter possess a peculiar character, which indicates more aquatic habits, or that they swim with more facility: their feet are smoother, flatter, and furnished with a fringe of hairs. Such is the 0. blanc, Bose. Hist. Nat. des Crust., I, 1. The Cumuru of Marcgrave belongs to this division(!). In classing the collection of the Museum d'Histoire N aturelle, we Roy. des Sc., by M. de Dlainville, this inequality of the forceps is peculiar to the males, at least such was the case in all the numerous specimens examined by him in his voyage to the East Indies. (1) For the Ocypodes of the western continent, see the observations of M. Say, Journ. Ac. Nat. Sc. Philad. His Ocyp. reticulatus is a Grapsus. Consult, also, the article Ocypode, Nouv. Diet. d'Hist. Nat., and the work of M. Desma· rest. DECAPOD A. 35 placed among the Ocypodes, under the specific name of quaclriden-t ta a crustaceous animal, which appears to us to bear a close re-sae m'b lance to the Gecarcin trois-epines, Desmar., a f oss1'1 spec1· es, Hist. Nat. des. Crust. Foss., VIII, 10; he suspects it may belong to the genus Thelphusa. . Here, at least in the females, the shell is very thm, membranous, and flexible and the body almost round or subovoid. The ocular pedicles are' sensibly shorter than in the preceding subgenera. p'1· rst comes the MroTYRrs, Lat. Where the body is subovoid, highly inflated, narrower and more obtuse before, and truncated posteriorly; the clypeus cousiderably diminished, and its extremity narrowed into a point. The claws form an elbow at the junction of the thiru and fourth joint, the latter of which is almost as large as the hand; the other feet are long, with angular tarsi. To these essential charactet·s we will add, that the ocular pedicles are curved and crowned with globular eyes; that the external foot-jaws are very ample, and their internal edge hairy, the second joint being very large, and the following one almost semicircular. Two species are known: one is found in the Australasian Ocean(l), and the other in Egypt(2), where it was observed by M. Savigny. Immediately after these come the PINNOTHEREs, Lat. Very small crustacea, which during a part of the year, in November particularly, inhabit various bivalve shells, chiefly the Mytili and Pinnre. The shell of the females is sub-orbicular, very thin and soft, while that of the males is solid, almost globular and somewhat narrowed into a point before. The feet are of a middling length and the claws straight and formed as usual. The external foot-jaws present but three distinct joints, the first large, transversal, and arcuated, ancl the second furnished at its internal base with a small appendage. The tail of the female is very ample and covers the whole under part of the body. The ancients believed that they resided with the Mollusca, in (1) Lat., Gener. Crust. et Insect., I, 40; Encyc., Method., Atlas d'Hist. Nat. ccxcvii, 3; Desmar., Consider., XI, 2. This subgenus, and that of Pimwtlteres, in the first edition of this work, constituted part of the Orbicularia; but in their natural 01•der they approach the Ocypodes, Gecarcini, &c. (2) Pl. d'Hist. Nat., of the great work on Egypt. |