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Show 138 CRUIST ACE.\. posterior extremity of the body blackish. From the vicinity of Nice. The remaining Phyllopa-AsPIDIPHORA, Lat.-have sixty pairsof feet, all furnished externally near their base with a large oval vesi. cle(I), and the two anterior of which, although lllUch larger and ramous, resemble antenn::e; a large shell, covering the greater part of the superior portion of the body, almost entirely free, clypeiform, cmarginated posteriorly, provided anteriorly in a circumscribed space with three simple, sessile eyes, the two anterior of which are largest and lunated; and two bivalve capsules containing the ova, and annexed to the eleventh pair of feet. Such are the characters which mark the APus, Scop., Which makes part of the genus Binoculus, Geoff., and of the Li· mulus, Muller. The body, including the shell, inclines to an oval, wider and more rounded before, and narrowed behind in the manner of a tail; ab· stracting the shell, it is at first nearly cylindrical, convex above, concave and divided longitudinally beneath by a furrow, and termi· nates in an elongated cone. It consists of thirty annuli, which are considerably smaller at the posterior extremity, and which, the last seven or eight excepted, give origin to the feet. The first ten are membranous, soft, without spines, exhibit a small button· like prominence on each side, and have each but a single pair of feet. The others are more solid or horny, with a range of small spines on the posterior margin; the last is larger than the preceding ones, nearly square, depressed, angular, and terminated by two arti· culated threads or set::e. In some species composing the genus LEPI· nuRus, Leach, a horny, flattened and elliptical lamina is seen between them. If the number of feet be about a hundred and twenty, the last annuli, beginning with the eleventh or twelfth, must necessarily have more than one pair, a circumstance which in this respect ap· proximates these Crustacea. to the Myriapoda. The shell, perfectly free from its anterior adhesion, invests a great part of the body, and thus protects the prirr•ary segments, which, as already stated, are softer than the others. It consists of a large, horny, extremely thin, and almost diaphanous scale or plate, which represents the superior teguments of the head and thorax united, and forming a large, oval, convex shield, angularly notched and dentated at its posterior ex· (1) Possibly annlogou11 to the vesicles forming the second joint of the feet of the DapbnillC. BRANCHIOPODA. 139 · Its upper Surface is divided b. y a transverse. line forming tremtt~. · two areas the antenor nearly semilunar, corres-ntted arcs, m ' · d 11 two ru h h d and the posterior to the thorax. In the m1 c e tot e ea ' pon mg bserve three closely approximated simple eyes, or fthe first, we o . d 0 • t facets the two anterior of w luch are largest an 'thout appat en ' 1 A d \VI ·r and the posterior much smaller and ova· u-lmost renuorm, f f 1 ar ature f h terior portion of the shell forms a sort o 1·onta , 0 t e an P tc d 'lunar shield beneath, which serves as a base to the Rattene ' semt h Th P osterior area, that which corresponds to the t orax, .la brum· . d the roughout the middle of its length. Th1' s s h e 11 · 1 15 on Y 15 carmate . f h · · t db t by its anterior extremity, so that lookmg rom t ts pom a eren · E h · d f th we can dt.s c over the whole back of the ammal. ac st e o e II from beneath and in a strong light, presents a large spot, she ' seen . 1 h. h rormed by numerous lines describing conce~tnc ova s, w IC ~ppear to be tu bu 1 a r and filled with a red fluid. Dtrectly under the shield o. r fr onta I d.ts k , we find the antennre and mouth. .T he former, twoh m b e inserted on each side of the mandtbles, are very s ort num er, ar · • Tl and filiform, and are composed of two nearly equal JOlDts. te mouth consists of a square, projecting labrum; of two strong, horny, t•n rte rt•o r 1y •m flated mandibles ' compressed and dentated at t.h e extre•- mity and without pal pi; of a large an~ prof~undly emargma:ed h- gu I a,. an d of two pairs of foliaceous . J. aws latd on eac. h othet, t.h e superior of which are spinous and cthated along the mner margm, and the inferior almost membranous and similar to small false feet; they are terminated by a slender, elongated join.t, and ar~ prolonged externally from their base into a species of auncle, ( ore~llette) furnished with a uniarticulated and ciliated appendage, winch may be considered as a kind of pal pus. According to Savigny( 1 ), the li· gula exhibits a ciliated canal which leads directly to the resophagus. The feet which amount to about one hundred and twenty, insensibly diminish in size commencing from the second pair; they are all strongly compre~sed, foliaceous, and are composed of three joints, exclusive of the two long threads at the extremity o~ the two anteriorfeet and the two leaflets at the end of the followmg ones, parts, which, ~hen united, we may consider as constituting a f?urth, forceps- like joint, or one with two elongated toes converted mt? ~ so~·t of antenniform threads. On the posterior side of the first JOmt 1s inserted a large, branchial, triangular membrane; the second also, on the same side has a red, vesicular and oval sac. On the opposite margin of th'ese feet are four triangular and ciliated leaflets, the superior of which is closely approximated to the toes of the forceps, (1) Mem. sur les Anim. 1ans Verteb., Savig., part I, fasc. I. |
