Latticed, having longitudinal lines or furrows, decussate by transverse ones. Lenticulate, doubly convex, of the form of a lens. Ligament, a solid body, softer than a cartilage, but harder than a membrane, which connects the valves in bivalves. Limb, the margin of bivalve shells. Linear, composed of lines. Lineate, marked with lines. Lip, the outer edge of the aperture of univalves. Littoral, of or belonging to the shore. Lobated, rounded at the edges. Longitudinal, the length of the shell from the apex to the base. Lubricity, slipperiness, smoothness of surface. Lunated, formed like a half moon. Lunulated, crescent-shaped. Lunule, a crescent-like mark or spot, situated near the anterior and posterior slopes in bivalve shells. Luniform, in the shape of a crescent. M. Margin, the whole circumference or outline of the shell in bivalves. Marginated, having a prominent margin or border. Membrane, a web of several sorts of fibres. Membranaceous, consisting of membranes. Mottled, clouded or spotted with various colours. Mucronate, ending in a sharp rigid point. Multilocular, many-chambered, consisting of several divisions. Muricated, clothed with sharp spines. N. Nacred, pearly, pearlaceous. Nemoral, of or belonging to a wood. Nited, glossy. Nodose, knotty. Nucleus, a kernel. O. Ob, prefixed to words, is used for inversely or inverted; as _obconic_, inversely conic; _obcordate_, inversely heart-shaped. Oblong-ovate, egg-shaped or oval. Obsolete, indistinct, not well defined. Ocellated, applied to eyelike spots. Ochreous, of the colour of yellow ochre. Offuscated, darkened, clouded, dimmed. Olivaceous, being of a greenish olive colour. Operculum, a lid which closes the aperture of some turbinated univalves; and also some of the tops of multivalves. Orbicular, spherical, circular, round. Order, the second division of the animal kingdom. Orders are made up of a plurality of genera. Orifice, an opening or perforation. Ovate, shaped like the longitudinal section of an egg. Ovoid, oval. P. Palmated, webbed, as in the feet of some water-birds. Papillæ, small dots or pimples. Papillary, } having the surface covered with dots or pimples. Papillous, } Papillose, pimpled, dotted. Papyraceous, thin as paper. Parasitical, living on some other body. Patulous, with a gap or opening. Pearlaceous, of or like mother-of-pearl. Partitions, calcareous processes, dividing the shells of the genus Nautilus, Serpula, &c. Pectinated, resembling the teeth of a comb. Pedicle, the support of the Lepas Anatifera, and its corresponding species, by which they are attached to wood, &c. Peduncle, a foot-stalk or tube on which anything is seated.