CELLULACEA. Bl. The second order of Cephalophora, Bl. consisting of doubtful microscopic bodies, with a number of variously arranged shells, as distinguished from the true Polythalamia, Bl. or chambered shells. See FORAMINIFERA. CEMORIA. Flemingii. Leach. A small patelliform shell, differing from Fissurella, in having the fissure placed behind the apex, which is produced, pointed and incurved. It is the Patella Fissurella, Müll. Patella Noachina, Chemn. F. Noachina, Sow. Puncturella, Lowe. Fig. 244. Cemoria Flemingii. Scotland and Tierra del Fuego. CENTRAL. A term used to indicate the position of the muscular impression of a bivalve shell when it is near the centre of the inner surface. It is also applied to the siphon perforating the septum of a chambered shell when it is placed near the centre of the plate. _Sub_-central is also used as a comparative term, to indicate the position of the siphon, or of the muscular impression, is _near_ the centre. Thus in Placuna (fig. 184), the muscular impression is central: in Exogyra (fig. 183), it is _sub_-central. CEPA. Humph. ANOMIA, Linn. CEPHALOPHORA. Bl. The first class of Malacozoæ, Bl. Divided into: _Order_ 1. Cryptodibranchiata; 2. Cellulacea; 3. Polythalamacea. The first consisting of Cuttle-fish, &c. which are destitute of shells; the second composed of those microscopic cellular bodies, which are regarded as shells by some authors; and the third containing the true chambered shells. CEPHALOPODA. Lam. (Cephalopodes.) ([Greek: Kephalê], _kephale_, head; [Greek: pous], [Greek: podos], _podos_, foot.) The fourth order of the _class_ Mollusca, Lam. containing molluscs, which are characterized by having a series of arms surrounding the head, which is placed above a sack-shaped body. This order is divided into Polythalamia, or many-chambered shells; Monothalamia, or single-chambered cephalopods; and Sepiaria, or cuttle-fish. Fig. 463 to 488. CEPOLIS. Montf. Belonging to the genus HELIX, Auct. CERATODES. Guild. ([Greek: Keratôdês], like a horn.) A genus composed of the flat, orbicular species of AMPULLARIA, Auct. which present so near a resemblance to the Planorbes, as to have been considered as belonging to them. Planorbis has, however, a horny texture, and no operculum, and it is always reversed, which may be observed by placing the spire upwards. Fig. 320, represents Ampullaria (Ceratodes) Cornu-arietis. CERIPHASIA. Sw. A sub-genus of Melanianæ, thus described, "Cerithiform; outer lip thin, dilated at the base; aperture small, slightly emarginate, without any internal groove; inner lip thin. C. sulcata, Sw. fig. 38. p. 204." (Sw. Lard. Cyclop. Malac. p. 342.)