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Show 372 MOLLUSCA. and increasing regularly in width to the end opposite the spire, which is more or less salient, according to the species(l). The animal is not known. The VoLUT A, Lin. Varies as to the form of the shell and that of the aperture, but is recognized by the emargination without a canal which terminates it, and by the salient and oblique plicre of the columella. From this genus Brugieres first separated the OLIVA, Brug., So named from the oblong and elliptical shape of the shell, the aperture of which is narrow, long and emarginated opposite to the spire, which is short; the plicre of the columella are numerous, and resemble strire; the whorls are sulciform. These shells are quite as beautiful as the Cyprrere(2). The animal has a large foot, the anterior part of which (before the head) is separated by an incision on each side; its tentacula are slender, and the eyes are on their side about the middle of their length. The proboscis, siphon and penis are tolerably long; but it has no operculum. MM. Quoy and Gaymard have observed an appen· clage on its posterior portion, which enters the sulcus of the whorls. The remainder of the genus Volu ta was afterwards divided into five, by M. de Lamarck(3). The VoLVARIA, Lam., Closely resembles the Oliva in its oblong or cylindrical form; but the aperture is narrow, and its anterior edge ascends to the top of the spire, which is excessive] y short. There is one plica, or seyeral, at the foot of the columella. The lustre and whiteness of this shell are such, that on some coasts it is used for making necklaces( 4). A small fossil species is found in the vicinity of Paris( 5). In the true Volutre or the · (1) Terebellum subulatum, Lam.,, Bulla terebellum, L. List., 736, f. 30, Encyc., 360, 1;-Tereb. convolutum, Lam., Sowerb., Gen. of Shells, No. VI. (2) Oliv. subulata, Lam., Encyc., pl. 368, f. 6, a, b,·-Vol. hiatula, L.;-Vol. porphyria, Vol. oliva, and, in general, all the cylindrical Voluta: of Gm., P· 3438, et seq. (3) Exclusive of the Tornatell:£ and PyramidellaJ already mentioned. (4) Volv. monilia, L.; Volv. triticea, Lam., &c. (5) Volvaria bulloi'dea, Lam., Encyc. Method., pl. 384, f. 4. GASTEROPODA PECTINIBRANCHIA T A. 373 VoLUTA, Lam., The apertu1·e is ample, and the columella marked with large plicre, the one furthest :rom t~e spire being the largest. The degree of projection in the sp1re vanes greatly. Jn some of them, CYMBIUM, Montf.; CYMBA, Sowerb., the last whorl is ventricose; the anima~ has a large, thick and fleshy foot, and a veil on the head, from the sides of which issue the tentacula. The eyes are on this same veil outside of the tentacula. The proboscis is tolerably long, and there is an appendage op. each side of the base of the siphon. They attain a large size, and many of them are extremely beautiful( 1 ). In others, VoLUTA, Montf., the last whorl is conical, becoming narrower at the extremity opposite to the spire(2). The foot of the animal is not so large as that of the preceding ones; their shells are frequently remarkable for the beauty of their colours or their arrangement. MARGINELLA, Lam. Form of the shell, similar to that of a true Vol uta; but the external margin of the aperture is tumid; the emargination is but slightly marked. The foot of the animal, according to Adanson, is very large, and has no ope1·culum. By turning up the lobes of its mantle it partly covers the shell. The eyes are on the external side of the base of its tentacula(3). M. de-Lamarck also distinguishes the CoLOMBELLA, in which the plicre are numerous, and the varix of the external margin is inflated in the middle( 4). It appears that the operculum is wanting. (1) Vol!!. mtltiopica, List., 797, 4;-V. cymbium, 796, 3, 800, 7;-V: olla, 794·, 1;-V. Neptuni, 802, 8;-V: navicula, 795, 2;-V: papillaria, Seb., III, lxiv, 9;V. indica, Martini, III, lxxii, 772, 773; genus MELo, Sowerb., Gen. of Shells, No. XXVill;-cymbiola, Chemn., X, cxlviii; 1385, 1386;-V: prreputium, List., 798, 1;-V. apectibilis, Davila, I, viii, S. (2) Vo/utq musica, List., 805, 14, 806, 15;-V. scapha, 799, 6;-V. vespertilio, 807,16,808, 17;-V. hmbrea, 809, 18;-V. vexillum, Martini, III, cxx, 1098;-V. ftavicam, lb., xcv, 922, 923;-V. wndulata, Lam., Ann. du Mus., &c. For the other specie~ consult the Memoir of M. Brode rip, Zool. Journ., Aprill825. (3) Volutaglabella, Aclans., IV, genus, X, 1;-Voluta faba, lb., 2;-Vol. prun~ m,Ib., 3;-Vol. persicula, lb., 4, and all pl. xlii, vol. II, of .Martini;- Vol. marKina/ a, Born., IX, 5, 6. (~) Volutamercatoria, List., 824, 43;-Vul. rustica, List., 824, 44;-Vol. mendiMI'la, and nearly all plate xliv of Martini, vol. II;-Ool. strombiformis,--Vol. labiOia;- Vol. punctata, &c., Sowerb., Gen. of Shells, No. JX. |