An illustrated and descriptive catalogue of recent bivalve shells, forming an appendix to the Index testaceologicus [by W. Wood].

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Página 188 - Shell rather thin, beaks placed about one-fourth of the length from the posterior extremity, ligament very narrow, anterior lunule distinct and obsoletely ribbed; basal margin slightly shortened; epidermis brownish; an obtuse, slightly elevated rib from the beaks to the anterior basal margin; lateral tooth rectilinear, rounded at the end, and parallel to the base; nacre very brilliant.
Página 71 - ... Shell more or less triangular and compressed, always longer than it is high, regular, equivalve, very inequilateral, posterior side shorter than the anterior ; umbones but little prominent, and nearly vertical ; hinge composed of two cardinal teeth, sometimes upon both valves, sometimes upon one only, and one or two lateral teeth more or less distant ; ligament external, short and swollen ; muscular impressions rounded, united by a pallial impression, which is straight and very much excavated...
Página 8 - Phila., 7:236; pl. 18, fig. 5. Shell elongated, with eight accessory valves, two of which are on the basal margin, extending nearly its entire length; anterior side gibbous, with the concentric lines lamellar, crowded, undulated and crossed by numerous impressed lines; valves much contracted sub-medially, with an oblique groove ; umbonal slope angulated ; posterior side with elevated laminae; extremity truncated; apophysis oblique, dilated; hinge margin within greatly thickened posteriorly. Length,...
Página 60 - Suboval, rlattish, much sloping on the anterior side, semistriated, and semi.pellucid, hinge with two teeth in one valve, and one in the other, pale yellow ; longitudinally radiated with pink ; half an inch long and three fourths of an inch broad.
Página 10 - Shell very thin, rather hyaline, transverse, ventricose; inside pearly; posterior side short, sometimes very short, rounded: anterior side more or less elongated, gaping; upper edge also gaping a little ; hinge with a small rather elongated, triangular pit, and a marginal lamina in each valve, to the outer part of which is attached the rather short external ligament. Muscular impressions two; these, as well as the muscular impression of the mantle, in which there is a large sinus, are indistinct.
Página 164 - Shell subtriangular, oblique, concentrically wrinkled, and longitudinally marked with numerous, hardly perceptible striae ; posterior margin very short and very obtusely rounded, a submarginal impressed line ; anterior margin very oblique and but slightly arcuated ; umbo placed far back ; within perlaceous, polished, edge strongly crenated ; teeth of the hinge robust, the posterior series very distinct and regular.
Página 151 - Shell somewhat oblique, very thick and ponderous, with from twenty-five to twentyeight ribs, each marked by an impressed line ; interstitial spaces equal to the width of the ribs ; umbones very prominent; apices remote from each other, and opposite to the middle of the hinge, spaces between them with longitudinal lines as prominent as their corresponding teeth ; anterior margin cordate, flattened, distinguished from the disk by an abrupt angular ridge ; posterior e'dge rounded, very short ; inferior...
Página 12 - Shell sub-elliptical, ventricose, with numerous prominent, slightly undulated, concentric striae ; a slight furrow extends from beak to base ; posterior side with radiating striae ; obsolete or wanting on the posterior slope; umbo prominent; posterior side short; cardinal tooth very erect, dilated, bi-marginate.
Página 4 - ... slightly wrinkled concentrically, the wrinkles regularly rounded towards the extremity ; hinge margin nearly rectilinear; basal margin a little arquated ; anterior tip rounded; posterior tip obliquely truncated, a little reflected, and rounded near the base ; hinge terminal ; teeth one in each valve, each having a flattened vertical surface, which turns upon that of the opposite tooth ; epidermis pale green.
Página x - TURTON'S MANUAL OF THE LAND AND FRESHWATER SHELLS of the BRITISH ISLANDS. A New Edition, thoroughly revised and with considerable Additions. By JOHN EDWARD GRAY, Keeper of the Zoological Collection in the British Museum.

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