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Show 38 CRUST .ACEA. claws are short and thick, and the other feet very flat;_ thC: fourth pair, and then the third are longer than the others; tars1 spmous. PL~GUSIA, Lat. The mediate antennre lodged in two longitudinal and oblique fissures traversing the whole thickness of the middle of the clypeus(l ). They are inferior or covered by this part in GnAPsus, Lam. Where the shell is somewhat wider before than behind, or at least not narrower, while in the Plagusire it widens from before backwards. The Grapsi are found throughout all parts of the globe, but are more particularly abundant in the vicinity of the tropics. They are not seen in Europe beyond 50° of latitude. If I mistake not they are called C~riques at Martinique. Marcgrave has figured some Brazi. lian species by the names of .llratu, .llratu-pinima ( Grapsus cruentatus, Lat.) and Carava-una. At Cayenne they are called Ragabeumba, or soldier. These animals conceal themselves during the day under stones, &c., at the bottom of the sea. I have been informed that some of them even climb up the trees on its shores and hide beneath their bark. The broad and flattened form of their body and feet enables them to support themselves for a moment on the surface of the water; they always walk sideways, sometimes to the right and at others to the left. Certain species inhabit rivers within the bounds of tide water, but most frequently live on their banks or on land. They assemble in great numbers, and when any one appeat·s among them, they hurry to the water with a tremendous noise, caused by striking one claw against the other. Their habits are similar to those of other carnivorous Crustacea(2). G. varius, Lat.; Cancer marmoratus, Fab.; Oliv., Zool., Adr ., II, 1; Cancre madre, Ron del.; Herbst., XX, 114. Size middling; nearly square, hardly broader than long; yellowish or livid; greatly elongated above, and marked with numerous fine lines and points of a reddish-brown; four flattened projec· (1) P. depressa, Lat.; Herbst., III, 35;--P. clavimana, Lat., Herbst., lix, 3; Desmar., Consider., XIV, 2. The tail appears to me to consist of but four dis· tinct segments. The third, however, presents one or two deep and transverse lines. In the Grapsi there are seven segments, the third of which has an angular dilatation on each side of its base. (2) See Bose, Hist. Nat. des Crust. DECAPOD .A. 39 tions arranged transversely at the base of the clypeus, and three teeth at the anterior extremity of each lateral edge. The tarsi are spiny. The G. porte-pinceau; Cuv. Regne Anim., .JV, xii, 1; Rumph., Mus. X, 2; Desmar., Consider., XV, 1, is remarkable for the numerous, long and blackish hairs with which the superior surfaces of the fingers are furnished. The tarsi are without spines, a character exclusively peculiar to this species. It is found in the East Indies( I). In our fourth section or the 0RBIOULATA(2), the shell is either sub-globular, rhomboidal or ovoid, and always very solid; the ocular pedicles are always short or but slightly elongated; the claws of unequal size according to the sex, those of the males being largest; there are never seven complete segments in the tail; the buccal cavity grows gradually narrower towards its superior extremity, and the third joint of the external foot-jaws always forms an elongated triangle. The posterior feet resemble the preceding ones, and neither of the latter is ever very long. In the CoRYSTEs, Latr., The shell is an ovoidal oblong, and crustaceous; the lateral antennre are long, projecting and ciliated; ocular pedicles of a mean size and separated; third joint of the external foot-jaws longer than the preceding one, with a visible emargination for the insertion of the next. The tail is composed of seven segments, the two middle ones obliterated in the males. A species-Cancer personntus, Herbst., XII, 71, 72; Leach, Malac. Brit., VI, 1, is known on the coast of France. The lateral edge of its shell is marked with three notches on each side. A second was brought from the Cape of Good Hope by the late Delalande. LEuoosiA, Fab. Form of the shell varying, but generally ovoid or almost globular, and always very hard and stony; lateral antennre and eyes very small; eyes approximated. The third joint of the external foot-jaws is smal1er than the second, and without any apparent internal sinus; (1) See the article Plagusie, Encyc. Method., and the Histoire des Animaux sans vertebres ofDelamarck, genus Grap8e. (2) The Orythi;;e and the Dorippes, in a natural series, would, in my opinion, belong to this section, and lead to the Corystes; their shell is a truncated ovoid. |