OCR Text |
Show 32 CRUSTACEA. widened form of the fore-part of the shell, as well as ·in their ocular pedicles, which, like those of the Podophthalmi, are long and slen. der, extending to the anterior angles, and inserted near the middle of the ft·ont. The claws of the males are long and cylindrical: such is the GoNOri.AX, Leach. Two species of which are found in European seas; one of them, howevet·, may possibly be a mere variety of the other. The first-Cancer angulatus, L.; Herbst., I, 13; Leach, Malac. Bt·it., XIII, has the anterior angles of its shell prolonged into a point, and a second, but smaller spine behind. Two others arc observed on the claws of the males, one on the joint called the arm, and the other on the internal side of the carpus; the hands are elongated, and somewhat narrowed at base; another tooth is found on the superior extremity of the thighs of the other feet. The body is reddish. It inhabits the western coast of France, and that of England. In the second-Cancer dwmboides, L., the shell presents no other spines than those formed by. the prolongation of the ante· rior angles. The body is smaller, and of a reddish-white or flesh colour. From the rocky localities of the Mediterranean(l). In the second division of the Quadrilatera, the fourth joint of the external foot jaws, or those which cover the other parts of the mouth ?e.low, is inserted in the middle of the extremity of the preceding JOmt, or more outwardly. Sometimes the shell is trapezoidal or ovoid, or is shaped like a h~art truncated posteriorly. The ocular pedicles, inserted at a short d1stance from the middle of its anterior margin, extend to its anterior angles, or even beyond them. . Commencing with those whose shell is transversely quadrilateral, w1dened before and narrowed behind, or which has the form of an egg, we first observe the MAOROPHTHALMUS, Lat. Where the shell, as in the Gonoplaces, is trapezoidal and the claws are long and narrow; the ocular pedicles are slender elongated and l_oc~ged in a ?'roove under the anterior margin of th; shell. Th; first JOlnt of the mtermediate antenn<E is rather transverse than Ion· gitudinal, and the two which terminate them are very distinct and (1) See the article Rhombille, Encyc. Methodique. DECAPOD.\. 33 of a mean size. The external foot-jaws are approximated inferiorly at their inner edge, leaving no interval between them, and their third joint is transverse. They(l) inhabit the Eastern Ocean and the seas of New Holland. The following, which constitute the subgenera Gelasimus, Ocypode, and JJfictyris, inhabit burrows, are remarkable fot· the celerity of their course, and have the fourth pait• of feet, and next to them, the third, longer than the others. The intermediate antennre are excessively small and hardly bifid at the extremity; the radical joint is neal'ly longitudinal. They are peculiar to hot climates. Here the shell is solid, of a quadrilateral or trapezoidal form, widest before. GELASIMUS, Lat.-Uca, Leach. Eyes terminating their pedicles like a small head; third joint of the external foot-jaws fot·ming a transverse square; last segment of the tail of the males almost semi-circular, that of the females nearly orbicular. The lateral antennre are longer and slenderer in proportion than those of the Ocypodes. One of the claws, now the right, and then the left, varying in individuals of the same species, is much larger than the other; the fingers of the small one are frequently shaped like a spoon or spatula. The animal closes the entrance of its burrow, which it excavates in the vicinity of the sea-shore, or in marshy places, with its large claw. These burrows are cylindrical, oblique, very deep, and placed close to each other, but are usually inhabited by a single individual. Their habit of holding the large claw in an upright position before the body, as if making an appellative gesture, has obtained for them the name of Calling-Crabs-Cancer vacans. One species, observed by Bose in South Carolina, passes the three winter months in its retreat without leaving it, and only visits the sea when about to spawn(2). •.•. ·'' I' (1) Gonoplax transversus, Latr., Encyc. Method., Hist. Nat., ccxcvii, 2;-Cancer brevis, Herbst., lx, 4. The Gonoplace de Latreille, a fossil species described by Desmarest, !list. Nat. des Crust. Foss., IX, 1-4, and perhaps also his G. incise, IX, 5, 6, may be a Macrophthalmus; generally speaking, however, his fossil Gonoplaces nre Gelasimi. The species he calls Gelasime luisante, VIII, 7, 8, does not appear to differ from the living one which I have called the maracoani, Encyc. Method., lb., ccxcvi, 1. (2) See the article Gelasime, Nouv. Diet. d'Hist. Nat., Ed. II, and the same article in the work of Desmarest on animals of that class. The Crabs, cietie-ete, cietie-panama, of Marcgrave, appear to me synonymous with the Gelasimus pugilator. According to the ob!lel'vations of M. Marion, communicated to the Acad. VoL. III.---E |