E. Ears, projections on the sides of the hinge. Echinated, set with spires. Effuse, spread out. Elliptical, oval. Elongated, drawn out. Emarginated, with the edge notched. Ensisform, sabre-shaped. Entire, whole. Epidermis, the outer coating of a shell. Equilateral, all sides alike. Equivalve, both sides alike. Exserted, protruding. F. Falcated, hooped like a scythe. Fasciated, covered with bands. Ferruginous, of an iron colour. Filament, a thread-like process. Filiform, thread-shaped, slender. Fimbriated, fringed. Fissure, a cleft or slit. Flexuous, zigzag, with angles widening. Flexure, a bending. Fluviatile, belonging to fresh water. Foliaceous, lamina or leave-shaped. Fragile, brittle, easily broken. Front, the aperture next the observer. Furcated, forked. Furrow, a trench or hollow. Fuscated, darkened, obscured. Fusiform, spindle-shaped, conical, or oval. G. Gaping, when the valves do not close. Geniculate, keeled. Genus, characters by which they are distinguished from others. Genera, plural of genus. Gibbous, bulged. Glabrous, having a smooth surface. Globose, globular, round. H. Hemispherical, in the shape of a half globe. Heterostrophe, shells whose spires reverse. Hispid, hairy. Hinge, the part where the valves are united. I & J. Jagged, denticulated, uneven. Imbricate, covered with scales. Imperforate, having no umbilicus. Inequilateral, when the anterior and posterior parts of the shell are dissimilar. Inequivalve, when the valves are dissimilar. Inarticulate, indistinct. Incumbent, one lying over the other. Incurved, bent backward. Indented, unequally marked. Inflated, tumid, swollen. Inflected, bent inward. Inflexed, bent towards each other. Intercostal, placed between the ribs. Interrupted, divided, separated. Interstice, space between. Intortion, turning or twisting. Involute, without a spire. Involution, that part which involves another. Juncture, the joining of the whorl in univalves. K. Keel, the longitudinal prominence in the Argonauta. Keeled, see Carinated. L. Labra, the lips. Laciniate, cut in irregular segments. Lacunose, surface covered with pits. Lamellar, films on plates. Lamellated, divided into distinct plaits or foliations. Laminæ, thin plates, laid one above another. Lanceolate, oblong, tapering like the head of a lance. Lateral, extending to one side from the centre. Latticed, see Decussated. Lenticulate, doubly convex. Ligament, a solid body which connects the valves in bivalves. Linear, composed of lines.