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Show 152 CRUSTACEA. The last subgenus of this subdivision, that of ANTHOSOMA, Leach, Approximates to Dinemoura in the presence of a siphon, nnd in the two caudal threads; but it is removed from it, as well as th preceding ones by its proj ecting antennce which resemble little mo~ nodactyle claws, and by its six last feet which are membranous united inferiorly, and folded laterally over the post-abdomen en: veloping it like a case; those of the first and third pait·s at·e u~guj. culated; the second feet are terminated by two short and obtuse toes(2). There, the body is oval, without salient caudiform appendages composed of threads or fin-like productions at its posterior extre~ mity. A portion of the superior teguments forms a shield, which does not cover its anterior half, is rounded and emarginated before widened and as if bilobate behind; then follow three pieces or scales' posteriorly rounded and emarginated, the second of which, and th; smallest of the three, is altuost in the form of a reversed heart; the last, and the largest, is arched. The four posterior feet are in the form of laminre, and are united by pairs; those of the first and th third are unguiculated; the extremity of the second is bifid The siphon is ~pparent •. The ova are covered by two large, oval,· conti~ ?'u.ous, cor1aceous p1eces, placed under the abdomen, and surpassing 1t m length. Such are the characters of the genus CEcRoPs, Leach, Of which a single species only is known. Cecrops Latreillii, Leach, Encyc. Brit., Supp. I, xx; 1, 3, the ~ale; 2, 4, the female; 5, the antennre magnified; Desmar., Con· s1d. L, 2. Found on the branchire of the Tunny and Turbot. The second tribe, that of the LERNEIFORMES, Lat., consists of Entomostraca, which approximate to the Lernere, in their external configuration, still more than the preceding subge· nera. T~ere are but ten feet visible(3), mostly very short, and but sl~ghtly or nowise adapted to natation. Sometimes the body IS nearly vermiform and cylindrical, the anterior R1.(s2so) . Jlntlwsoma Smithii, Leach; Desmar. ' Consid ·' L , 3·, Caligua imbricatiJI, (3) There are probably two mor . h . either indistinct or hav h e, .as 10 t e precedmg subgenera, but they are e sue a pecuhar form that they have not been recogni~ed. PA:CILOPODA. 153 segment be~ng ~erely somewhat wide.ned and furnished with two projectmg didactyle claws; somettmes, on account of two lateral expansions resembling lobes or wings behind the thorax, and of two posterior ovaries, it forms a small quadrilateral mass. Thi~ tribe is composed of two genera. In the first or the DicHEJ...ESTIUM, Herm., Jun. We observe a nal'I'OW elongated body, slightly dilated before, and composed of seven se~ments, the anterior of which-the thorax of Herm.-is wider than the others, rhomboidal, and formed of the head and a portion of the thorax united. It bears: 1, four short antennre, of which the lateral are filiform and consist of several joints, and the intermediate project like little arms and are quadri-articulated, the last joint terminating in a didactyle claw; 2, an inferior, membranous, and tubular siphon; 3, three kinds of deformed palpitwo multifid feet?-on each side, placed on an eminence; 4, four prehensile feet, the two first of which consist of a thigh and leg terminated by various unequal and dentated hooks, and the others of an enlarged thigh terminated by a small but stout nail. The second and third segments are almost lunulated, each bearing a pair of feet formed of a single joint, terminated by two kinds of toes, dentated at the end. To the fourth segment is attached anothet· pair of feet, the fifth and last, but having the form of simple, oval, divergent, and immovable vesicles, which Het·mann presumes are rather ovaries than feet. This segment, as well as the next, is nearly square. The sixth is much longer, and cylindrical. The seventh and last is three times shorter, almost orbicular, flattened and terminated 'by two small vesicles. The eyes are not distinct. Dichelestium sturionis, Herm., Jun. Mem. Apter. P· 125, V, 7, 8; Desmat·., Consid. L, v. About seven lines long and one broad. The second segment is prolonged on each side into an obtuse papilla, and the four following are red in the middle, with whitish-yellow along the lateral margins. When viewed from above, the feet are not visible. This animal penetrates deeply into the skin and places itself on the osseous arches of the branchire, but without, as it appears, intruding upon their combs. Twelve of them were taken by Hermann from a single fish. Of this number, two or three, perhaps males, were one third shorter than the others, and had a curved body; one of the twelve lived three days. They are constantly whirling about, attd with considerable vivacity. By means of their ft·ontal claw:; they at·e enabled to cling with great tenacity. Vo1 .. III.-U |