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Show 370 MOLLUSCA. form of the columeiJa, furnish the grounds of its division into genera, which may be variously grouped( I). CoNus, Lin.(2) So called from the conical shape of the shell; the spire, either perfectly flat, or but slightly salient, forms the base of the cone, the apex being at the opposite extremity; the aperture is narrow, rectilinear, ot· nearly so, extending from one end to the other without enlargement or fold, either on its edge or on the columella. The thinness of the animal is proportioned to the narrowness of the aperture through which it issues; its tentacula and proboscis are highly protractile; th~ eyes are placed on the outer side of the f01·mer, and near the point; the operculum, situated obliquely on the hind part of the foot, is too narrow and short to close the whole of the aperture. The shells of this genus, being usually omamented with the most beautiful colours, are vet·y common in cabinets. The seas of Europe produce very few(3). They are distinguished by the flatness or slight projection of the spi.re; by the whorl.s being tuberculated ·or not; by its being more sahent and even pomted, and furnished, or not, with tubercles. There at:e s~me in which th~ spire i3 sufficiently salient to give them a cyhndrtcal appearance, m which case it may be either smooth or tuberculated( 4·). The appellation of crowned spire is applied to that which is studded with tubercles. CYPRJEA, Lin. The spire projecting but little, and the aperture narrow and extend· ( 1) They are the Paracephaloplwra Dioica Siplwnobranchiata of Blain ville . . (2) ~· de Blainville unites the Coni, Cyprem, Ovulm, Terebella, and the Volutm, m a fam1ly which he calls ANoYOS'.rOllu. • In pla.cing here the genera with a straight aperture, we must not be understood as meanmg to approximate them to the preceding family but only to present th. em first. ' as po ssess·m g th e most str1· k·m g characters of all 't hose which are fur· mshed w1th a siphon. (3). :or ~he species of this beautiful genus see the article and the plates of Brugiercs m the Encycl. Method., where they are extremely well described and figured, and the enumeration still more complete than in the Ann. dlt Mus., XV, by M. de Lamarck. ( 4) Species with a crowned spir~: Con. cedonulli L. a shell much sought for and 0 f h' I 1 ' ' ' w lCl t1e1·e are many varieties, Encycl. Method. pl. 316 f. 1· Con. mar· moSre us' . L ., E. nc., ~ 1· 317, f: 5;-Con. arenatus, Brug., E'n cycl, p' l. 320' , f. 6, &c. t P 1 ;cJes With a Simple sp1re: Con. litteratus, L., Encyc. pl. 323 f. 1·-Con. tue tatu8 ' ll rug., E nc., pl. 326, f. 7;-Con. virgo, Brug. En' c. pl. 326' , f. 5, ' &c. GASTEROPUDA PECTINlllHANCIIIAT A. 371 ing from one extremity to the other; but the shell, which is protuberant in the middle, and almost equally narrowed at both ends, forms an oval, and the aperture in the adult animal is transversely wrinkled on each side. The mantle is sufficiently ample to fold over and envelope the shell, which at a certain age it covers with a layer of another colour, so that this difference, added to the form acquired by the aperture, ~ay easily cause the adult to be ta.ken for another species. The ammal has moderate tentacula, \Vlth the eyes at their external base, and a thin foot without an ?perculum. The colours of these shells, also, are extremely beautiful; they are extremely common in cabinets, though with very few exceptions they all inhabit the seas of tropical countries( 1 ). In the OvuLA, Brug. The shell is oval, and the aperture narrow and long, as in Cyp1~a, but without plic<£ on the siue next to the columella; the spire is concealed, and the two ends of the aperture equally emarginated, or equally prolonged in a canal. Linn<Eus confounded them with the Bullre, from which Brugieres has very properly separated them. The animal has a broad foot, an extended mantle which partly folds over the shell, a moderate and obtuse snout, and two long tentacula, on which at about the third of their length, are the eyes. ' . Montfort particularly designates, by the term OvuL.JE, those In which the external margin is transversely sulcated(2). Those in which the two extremities of the aperture are prolonged into a canal, and in which the external mat·gin is not sulcated, he calls NAVETTES VoLV.JE(3). When this external margin is not sulcated, nor the extremities or the aperture prolonged, he styles them CALPURN.JE( 4). TEREBELLUM, Lam. An oblong shell, with a nanow aperture, without plicre or wt·inkles, (1) For the species see the genus Cyprma, Gmel., and the figures collected by Brugieres for the Encyclop., the Gen. of Shells of Sowerby, No. XVII, and par· ticularly a Monograph by M. Gray, published in the Zool. Journal, Nos. 2, 3, and4. ~) Bulla ovum, L., List., 711, 65, Encyclop., 358, 1. (3) Bulla volva, L., List., 711, 63, Encycl., 357, 3;-B. birostris, Encycl., 357 1; Sowerb., Ib. 4) Bulla verrucosa, L., List., 712, 67, Encyc., 357, 5, fi·om which we do n~t separate the ULTIMJE, Montf.: or Bulla gibbosa, L., List., 711, 64, Encyc · 357, · |
