OCR Text |
Show 56 CRUSTACEA. represents them, are thrown on the side and do not form with the last segment a flabelliform fin. The ocular pedicles are generally longer than those of the Ma. croura belonging to the following sections. Here (the Hippides, Latr. ), all the superior teguments are solid. The two anterior feet sometimes terminate in a monodactyle hand, or one without a pnger, in the manner of a palette, and sometimes in a point; the six or four following ones end in a fin; the two last are filiform, reflexed, and situated at the inferior origin of the tail. The latter becomes suddenly narrowed immediately after the first segment which is short and broad; the last is in the form of an elongated triangle, and the lateral appendages of the penultimate in that of curved fins. There are four pairs of sub-caudal appendages, composed of a very slender and filiform stem. The antennc:e are very pilose or strongly ciliated; the lateral first incline to the intermediate, and are then arcuated or contorted outwards. ALBUNEA, Fabr. The two anterior feet terminated by a very compressed triangu· lar, monodactyle hand; the last joint of the following ones falciform. ' The lateral antennc:e are short, and the intermediate ones are termi· nated by a single long and setaceous filament. The ocular pedicles occupy the middle of the front, and form, together, a sort of flat trian· gular snout, with the external sides arcuated. The shell is almost plane, and nearly square; the posterior angles are rounded, and their anterior margin finely dentated. The only well known species, Cancer symnista, L.; .IJ.lbttnea symnista, Fabr., Herbst., XXII, 2; Desmar., Consider., xxix, 3, inhabits the Indian Ocean( 1 ). If the Cancer carabus of Linna:!us belong to the same subgenus, a species would be found in the Mediterranean. HIPPA, Fab.-EMERITA, Gronov. The tw.o anterior feet terminated by a strongly compressed, nearly ovo1d and adactyle hand; the lateral antennre much shorter than the intermediate, and contorted; the latter ter·minated by two short, obtuse filaments placed one on the other; the ocular pedicles (1) M. Desmarest hesitatingly places the genus Posydon of Fabricius wh() speaks of two :species, near the Albunea:; but according to the latter the an 1 terior ante~na: are b1fid, a character which does not belong to the Albunea:. Owing t() ~e ~~perfect manner in which he describes this genus, we are not able to rec()g· mze 1t, or to appreciate its affinities. DECAPODA. 57 long and filiforr.1, . and the thil·d joint of the foot-jaws vcr·y large and Jaminiform, emarginated at the end and covering the cn~uing joints. The shell is neady ovoid, convex, and tnmcated at both ends. The last joint of the second feet and of the two following pairs is triangular, but approaching, in the latter at least, to the form of a crescent; the two last of the fourth pair arc turned up, and laid on the two preceding ones; the first segment of the tail is marked with two impr·essed and transverse lines( 1 ). REMIPEs, Lat. The .two anterior feet elongated, the last joint conical, compr·es;ed, and hau·y; the four antennc:e closely ,approximated, very short, and nearly of an equal length, the intermediate ones terminated by two fllaments; ocular· peclicles extr·cmcly short and cvlinclt·ical· external foot-jaws in the for·m of small claws, thinned ~nd arcua~ccl at the end, and ter·minated by a stout hook. The shell is shaped like that of the Hip pee. The last joint of the second and third feet fot·ms a tl'iangular blade, with. an .emargination in its extet·nal side; the same joint of the fourth 1s tl'Iangulal', nal'row, and elongated. As in the Hipp::e, the first caudal segment presents two impressed and transverse lines. Two species arc known; one f1·om the Australian Seas(2), and the other· fl'Om the Antilles, and the coast of Bt·azil. There (the Pagurii, Latt·.), the teguments are somewhat crustaccous, and the tail is most commonly :;oft, contorted, and in the form of a sac. The two anterior feet terminate in a didactyl ~ hand, the four foll~wing ones in a point, and the four postcr·ior, which are shol'ter, 111 a sort of fol'ceps or little didactyle hand. The first joint of the peduncle of the lateral antenn::e presents a pointed or· spinifot·m appendage or projection. Thes~ Crustacea, .termed Ca1·cinion by the Greeks, and Cancelli by the Latm.s, .usually Inhabit empty univalve shells. Their tail, that of the ~1rg1 excepted, presents but three false feet, (in the females on.ly), sttuated on one of the sides, each of which is divided into two filtform and hairy branches. The three last segments arc suddenly nan·owed. In some of them, such as the (1) Hippa a~r:ctyla, Fab.; fl. emeritus, Id.; Cancer emeritus, L.; Emerita, Gronov., Zoop .. ' xvu, 8, 9; Herbst., xxii, 3; Desmar., Consider., xxix, 2 in the seas of both Ind1es. ' (2) Remipes testudinarit£&, Latt·.; Desmar., Consid., xxix, 1; Cuv., Regnc Animal, IV, xii, 2. VoL. lli.-H , |