Glossary of snail terms used in the key. Snail images followed by descriptions of terms.

aperture – the opening in a gastropod shell.

appressed – pressed or applied closely against something, adherent.

calcareous - composed of calcium carbonate, chalky. 

campanulate – formed like a bell, bell-shaped.

carina/carinate – a pronounced or prominent keel or keel-shaped formation, a projection like a spiral ridge, knife-edged ridge; carinated: angled, applied to any shell having a raised thin ledge, passing round a whorl or any other part of the shell; with a sharp keel or ridge; revolving sculpture, sharp.

channeled – grooved or formed like a channel; passage with a deep furrow or groove.

columella – the axial pillar, the central pillar of the shell around which the whorls are build, extending from the apex to the base; a portion of the columella is seen at the aperture of most spiral univalves.

concentric – lines or ridges curving about a center.

conical – cone-shaped.

corneus – consisting of a horn or horn-like texture, material is similar to a horn or hoove.

costate – having costa or rib-like structures; costa: rounded ridge on the surface of a shell, larger than a cord.

depressed – lowered in position, pressed or kept down, flattened from above.

dextral – having the whorls of a spiral shell turning toward the right, twisting to the right side or right hand when the apex is upward.

discoidal  flat, all whorls in one plane.

elevated – when the spire cone advances more in height than in width

ellipsoid – oblong with rounded ends, oval shape

globose – rounded, sphere-shaped, like a globe or ball

hirsute – covered with coarse hairs or hair-like processes, set with bristles, shaggy.

keel - a ridge or edge at the shoulder of the whorls.

lamellae – (lamellate) a thin plate, flared axial projections of the outer lip occurring at various stages in the shell growth.

lirae – fine raised lines or fine grooves on the shell surface, ornamented with sharp, raised threads, marked with parallel grooves or ridges

malleated – appearing as though hammered.

multispiral – consisting of many whorls, or a well-defined spiral that covers the entire operculum of the snail.

obtuse – blunt or rounded at the extremity, not pointed

operculum – a horny or shelly plate serving to close the aperture

ovate – egg-shaped, oval

parietal wall – inside wall of snail within the aperture, the broader upper portion of the inner lip.

paucispiral  - only slightly spiral, as in some opercula.  Paucispiral opercula are often distinguished by a small, spiral nucleus that is deflected to the side of the operculum.

periostracum – a skin or horny covering on the exterior of many shells, a protection against erosion; sometimes thin and transparent, like shellac, or think, fibrous, or hairy.

peristome – the thickened rim or lip around the mouth; the lip or margin of the aperture of a spiral shell

planispiral – shells coiled in one plane like  a flat spiral with symmetrical sides; although sides can be somewhat assymetrical.

protoconch – the embryonic shell of a snail, frequently different in design, texture, or color from the adult shell.

punctate – covered or studded with dots over the surface, dotted

radial  - extending from a center in a manner of rays

ribs  - a long and narrow ridge, strip, a firm rib-like elevation

riblets – small ribs.

rimate – provided with a very small hole or crack, a fissure, a chink

septum (septate) – a calcareous plate or partition,

shouldered –ridged, as the whorls in some gastropods

sinistral – having the whorls of a spiral shell turning toward the left, twisting to the left side or left hand when the apex is upward.

spire – the whole series of whorls of a spiral shell except the last one

striae – superficial furrows or very fine lines which cross the surface of the shell in different directions.

sulcus – a groove, longitudinal furrow.

suture – the line of junction or seam along which two hard structures join, a continuous spiral line marking the junction of whorls in a gastropod shell.

teeth – the toothlike structures in the aperture of some shells

transverse – lying across, crosswise, bands or striae running across the shell at right angles to the axis.

truncate – cut off, terminating abruptly

turbinate – top-shaped, the coils piled on one another and tapering from a broad base to the apex, conical with a round base.

turriform- tower-shaped, spire whorls regularly stepped in outline forming a long spire with somewhat shouldered whorls, screw shells.

umbilicus/umbilicate – an indention or cavity or a circular depression at the axial base of a spiral shell

whorl –a turn of the spire of a shell

Return to main key

Definitions based on: Winifred H. Arnold. 1965. A glossary of a thousand and one terms used in conchology. The Veliger, vol 7, supplement.

Shell drawings by Brittany Harried modeled after Burch 1980.