The Elements of Fossil Conchology; According to the Arrangement of Lamarck; With the Newly Established Genera of Other Authors (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1843 edition. Excerpt: ...' Section 2. Carinated, volutions flat above. Example, P. marginatus. Section 3. Pellucid, spire deeply umbilicate; volutions slightly carinaled, and lenticular. Example, P. nitidus. The upper side or apex of the shells of this genus, is that in which the volutions terminate in the centre, generally in a point, with the aperture next the left hand; the umbilicus will he found on the opposite side. The shells of this genus are found in stagnant waters, ditches, lakes, and also in slow running streams. Their geographical range seems limited to Europe and America, and those of the latter country have a thickened lip. Fossil species are found in the fresh water formations at Paris, and the Isle of Wight. TRIBE IX.--COLIMACEA. Shell spiral; external surface smooth, exhibiting only the lines of growth; right margin of the aperture frequently reflected outwards; animals terrestrial, with cylindrical tentacula, some species with an operculum, and others devoid of one. SUB-DIVISION I. Animals with two tentacula. Genus LXXVIII.-CYCLOSTOMA.--Lamarck. Generic Character.--Shell thin, turbinated, variable in shape, the apex in most species obtuse, and the volutions ventricose; aperture entire, circular, or nearly so, in the adult state; peritreme, or outer lip, more or less angular at the upper parts united all round, sometimes thickened, usually reflected, and frequently externally fringed; operculum spiral, generally horny, but inclining to testaceous in some species; consisting of a few depressed convolutions, provided with a simple testaceous internal coating'. C3/clostoma antiqua. Plate IV. fie. 5. Several of the species approach nearly in form to the Paludinaa and Valvatte, but the orbicular aperture, and entire outer lip at once...