COLUMELLA. PILLAR; the middle column about which the wreaths form their spiral circuit.

abrupta. Abrupt; truncate at the base. caudata. Caudate; elongated so as to project beyond the body.

plana. Flat; extending into a plain lip. plicata. Plicate; marked with transverse folds. spiralis. Spiral; caudate and spirally twisted. COSTE. RIBS; keel-like processes reaching from the apex to the periphery of the shell. fornicatæ. Arched; beset longitudinally with hollow scales.

DIGITI. CLAWS; digitate or finger-like lobes of the outer lip.

DORSUM. BACK; the upper part of the body when laid on the aperture.

EPIDERMIS. SKIN; a membranaceous covering of the shell, found on some but not on all species.

GENICULA. GENICULATIONS; the contraction of

the whorls so as to correspond with the internal divisions or dissepiments.

LABIUM. LIP; the internal or columellar marinterius. gin of the aperture.

In the Patellæ this name is given to a testaceous membrane in their concavity called fornicale when under the vertex, and laterale when it constitutes a chamber in the side.

exterius, LABRUM. The outer margin of the aper

ture.

anticum. Anterior part; next the spire. posticum. Posterior; that nearest the rostrum. coarctatum. Coarctate; drawn back to the base. digitatum. Digitate; divided into attenuated diverging lobes.

solutum. Disengaged; separated from the whorls by a sinus or gutter.

fissum. Cloven; almost divided in the middle by a linear sinus.

mucronatum. Mucronate; projecting in one single sharp point.

OPERCULUM. LID; a plate or door with which some species close the aperture of their shells it is either of a horny, testaceous,

or membranaceous substance, and varies much in shape and contexture.

RADII. RAYS; elevated striæ tending from the centre to the periphery.

ROSTRUM. BEAK, formed by both lips being produced towards the base into an attenuated or narrow process.

SIPHO SEU SIPHUNCULUS. SIPHON ; a small cylindrical canal perforating the partition in a chambered shell, is either centralis, through the centre; lateralis, through the margins of the partitions; or obliquus, cutting the axis of the whorls.

SPIRA. SPIRE; the upper whorls collectively. cariosa. Carious; corroded, or, as it were, worm

eaten.

capitata. Capitate; terminated by an obtuse

head.

exquisita. Exserted; much attenuated.

plana. Flat; having the upper whorls of an equal height, so that the spire appears truncate. retusa. Retuse; having the lower whorls of the spire pressed into the body..

retuso-umbilicata. Retuso-umbilicate; the spire being so much impressed as to seem rather concave than convex.

SUTURE. SUTURES of the whorls; the spiral line of connexion between them.

duplicate. Duplicate; with a double elevated

line or stria.

marginata. Marginate; raised, with a promi

TESTA.

nent keel.

SHell.

antica. Anterior (part); that which is towards the spire.

clavata. Clavate; club-shaped, thicker above and elongated towards the base.

convoluta. Convolute; when the exterior whorls spirally involve the interior.

corticata. Corticate; covered with an epidermis. cylindrico-umbilicata. Cylindrically umbilicate; the umbilicus of which is a cylindric cavity. emarginata. Emarginate; having the margin excavated by a sinus.

exumbilicata. Imperforate; destitute of a hollow

umbilicus.

fusiformis. Fusiform ; intermediate between conical and ovate, or tapering and a little

ventricose.

imbricata. Imbricate; with plaits parallel to the

margin.

interrupta. Interrupted; continued by new accretions, or additions of the shell.

involuta. Involute; having the margin of the exterior lip turned inward.

lineis crisputa. Wrinkled; rendered rough by flexuous lines.

marginata. Marginate; the sides of the shell being thickened.

obovata. Obovate; nearly oval, but narrower and produced at the base instead of the apex. perfoliata. Perfoliate; having a horizontal suture girt with a deflex or overhanging margin, as if one shell were placed upon another. polythalamia. Chambered; divided internally by various partitions.

radicata. Radicate ; affixed by the base to some foreign substance.

rostrala. Rostrated; beaked.