OCR Text |
Show 70 CRUSTACEA. The antennre always pt·oject; the laterals are usually very long and resemble very fine setre; the intermediaries of a great number ter. minate in three threads. The eyes are closely approximated. The external foot-jaws, more elongated and nart·ow than usual, resemble palpi or antennre. The mandibles of most of them are compressed and arcuatecl at the extremity. One of the first pairs of feet is fre. quently flexed upon itself. The segments of the tail are dilated 01• widened laterally. The external leaflet of its terminal fin is always divided in two by a suture, a character observed nowhere else ex. c.ept in the la~t Crustacea of the preceding section; the azygous por. twn of the mHidle, or the .seventh and last segment is elongated, narrowe~ near the extremity and provided above with ranges of small spmes. The false feet, of which there are five pairs, are elon. gated and usually foliaceous. Immense n'!mbers of these Crustacea are consumed in all pa1·ts of the world. Some species are even salted in order to preserve them. In some of them, the three first pairs of feet form a didactyle claw, the length of which progt·essively augments, so that the third pair is the longest. Such arc the PENJEus, Fab., Where there is no annular division in any of the joints of the feet. Their mandibular palpi are turned up and foliaceous. A Jittl elli?tical appendage may be seen at the base of the feet, a chat·acte~ w~Ich s:ems to approximate them to Pasiphrea, the last genus of this sectwn, and to those of the following one. Some, all indigenous to Europe, on account of the shortness of the two threads of their intermediate antennre, form a first division. It contains the following species. P. sulca.tus; Palremon sulcatus, Oliv., Encyclop.; Caramote, Rond., H1st. Nat. des Poiss ., liv • xv1'I't' ' chap · 7 . N'm e I· DC1lC S long; on the middle of the thorax a longitudinal carina bifurcated a 1 t base, ter1m~n~ted by a projecting rostrum, compressed, with e.even teet 1m Its upper edge and one in the lower; a longitudmal sulcus along each side of the carina. This species is very common in the Mediterranean and the object of considerable commerce. It is salted and shipped to the. Le:ant.. The P. trisulcatus., Leach, Malac. Brit. XLII, wh~ch mhabits the coast of England, is perhaps a mere local variety of the sulcatus. Its thorax is trisulcate and the ros· truro bidentate beneath. In the P. d'Orbigny -L t N n· d'H' . , a , ouv. 1ct. Ist. Nat., Ed. II, article Penee, the carina is not sulcated. DECAPOD A. 71 The intermediate antennre of others are terminated by loBg threads; they constitute our second division to which we. refer. Pen::eus monodon, Fab.; Squilla indica, Bont., H1st. Nat., P· 81, which inhabits the Indian Ocean. P. antennatus, Risso, Crust., II, 6, and P. mars, Id., II, 5, also appear to belong to it. STENorus, Lat. Distinguished from the Penrei by the transverse and annular divisions of the:: two penultimate joints of the four posterior feet. The entit·e body is soft; the antennre and feet are long and slender, those of the third pair widest. · But a single species is known. It was brought from the seas of New Holland by M. P6ron and Lesueur. Olivier retains it in the genus Palremon-Cancer setiferus, L.; P. hispidus, Oliv., Encyclop. and Atl., d'Hist. Nat., CCCXIX, 2; Seba, Mus., III, XXI, 6, 7; Herbst., XXXI, 3, where I first placed it. 'fhe remaining Carides, the interme~iate antenn::e of many of which are terminated by three threads, have at most but two pairs of didactyle claws formed by the four anterior feet. A subgenus founded on a single species peculiar to North Ame-rica, that of ATYA, Leach, Is removed from all analogous Crustacea by an anomalous character. The forceps terminating the four claws is cleft down to its base, or seems to be composed of two fingers in the form of thongs united at their origin; the preceding joint is crescent-shaped. The second pair is the largest. The intermediate antennre have but two threads. In all the following subgenera, the blades of the forceps originate at a certain distance from the base of the penultimate article, or of that which bas the form of a hand; the body or the part that precedes it is not lunulated. We now have in the first instance those Carides whose feet are generally robust and not filiform, and which have no appendage to their external base. Their body is neither very soft nor greatly elongated. Among these subgenera, whose feet are deprived of this appendage, the three following present an insulated form with respect to theil· claws. CRANGON, Fab. The two anterior claws, which are larger than the subsequent feet, |