Adpressed: Joined by overlapping; the opposite to impressed.

Anal canal: A canal, normally open, at the upper (or posterior) end of the gastropod aperture, through which solid waste matter is voided.

Ancillid groove: A spiral groove below the centre of the body whorl on ancillid shells.

Angulation: Formed from corners; angled.

Anterior: At or towards the front or head end of a shell.

Anterior canal: An open or closed tubular shell extension at the anterior end of a shell, through which the siphon is extended. Same as siphonal canal

Aperture: The major opening of a gastropod shell.

Aperture entire: Uninterrupted; without an anterior notch.

Apex: The tip of the spire.

Apical whorls: Those whorls near the apex.

Axial: Pertaining to or more or less parallel to the axis of coiling of a gastropod shell.

Axial sculpture: Sculpture running parallel to the axis in a gastropod shell.

Axis: An imaginary line through the apex of a gastropod shell, about which the whorls are coiled.

Basal: Pertaining to the base.

Basal margin: In a gastropod shell, the angled portion of the body whorl separating the base from the remainder of the whorl.

Base: In coiled gastropods, the zone below the periphery of the body whorl. 

Bead: A small, more or less hemispherical protuberance resembling a bead. Beads are smaller than nodules.

Beaded: Sculptured so as to resemble beads, or strings of beads.

Below: In a gastropod, situated more towards the anterior end.

Benthic: Living on the seabed

Bifid: Having two parts.

Body whorl: The most recently formed whorl of a gastropod shell, terminating in the aperture.

Bottom: In a gastropod shell, the anterior end.

Calcareous: Made of, or mostly, calcium carbonate.

Callus: Calcareous thickening

Canaliculate: Prominently grooved; channelled.

Cancellate: A sculpture produced by axial ribs crossed by spiral ribs of about the same size and spacing, giving a lattice-like appearance. Latticed.

Carinate: DONT USE. Use 'keeled'

Columella: A pillar surrounding the axis around which the shell is coiled, formed by the inner surface of the whorls. The wall opposite the outer apertural lip.

Columellar: Pertaining to the columella.

Columellar deck: In nerites, the area on the ventral surface of the shell covered by the columellar callus.

Columellar pillar: The lower end of the columella, particularly in ancillid shells.

Columellar shield: A plate of callus, most evident in the family Cassidae, extending from the columella onto the ventral shell surface.

Concentric: DONT USE. Use 'spiral'

Congeneric: In the same genus.

Conspecific: The same species.

Cord: DONT USE. Use rib, riblet or thread.

Corneous: Made of horny material.

Coronate: With tubercules or nodules around the shoulders of the whorls

Crenulate: Having a regularly notched or scalloped edge.

Decollate: With the apex broken off.

Denticle: A small tooth-like projection.

Denticulate: Toothed.

Dextral: Coiled with a right hand spiral. i.e. clockwise when viewed from the apex.

Dorsal: Of, pertaining to, or situated on the back or upper surface; in a gastropod shell, opposite the aperture. Opposite to ventral.

Dorsum: The dorsal surface of a shell.

Endemic: Peculiar to a region

Entire: Continuous; having no breaks. When applied to the aperture of a gastropod, the aperture in not interrupted by an anterior or posterior canal.

Eroded: Worn away.

Fasciolar band: Fasciole

False umbilicus: An umbilicus-like opening found in some gastropods, but not the true umbilicus.

Fasciole: A raised spiral band near the anterior end of some gastropod shells, formed by successive edges of the anterior canal.

Fenestrate: Literally, windowed; having a sculpture of crossed axial and spiral ribs or riblets, forming rectangular pits as in a multi-pane window.

Flaring: Opening or spreading outwards; said especially of the outer lip of the aperture.

Fold: A major constriction or gathering of the shell surface.

Foliaceous: With thin, leaf-like lamellae.

Foot: The muscular ventral part of the gastropod body used for locomotion.

Fossula: A pit or depression on the anterior part of the inner lip.

Frond: A foliaceous, leaf-like extension of a sculptural element, as on a varical spine

Funicle: Spiral ridge running into the umbilicus.

Fusiform: Spindle shaped; swollen at the centre and tapering almost equally towards the ends.

Granulose: Grainy or finely pustulose; covered with granules.

Growth line: More or less axial line representing former resting position of the outer lip.

Height: Distance from the apex to the anterior tip of a gastropod shell. Also called length.

Heterostrophic: The protoconch coils in a different direction to the rest of the shell; usually applies to the protoconch coiling sinistrally and the teleoconch dextrally.

Holotype: The single specimen designated as the type by the original author of a species name at the time of the original description.

Homonym: One of two or more identical but independently proposed names for different species, genera or taxa.

Imbricated: With scales overlapping each other like roof tiles.

Impressed: Joined by forming a groove; opposite to adpressed.

Inner lip: The lip of the aperture closest to the axis of coiling of a gastropod shell. (Not the inside of the outer lip).

Intertidal: Living between high and low tide levels.

Intervarical: Between the varices.

Keel: A sharply raised ridge, with parallel sides, as in the keel of a ship.

Lamella: (Pl. lamellae). A thin plate or scale, more or less erect. See also scales.

Latticed: Having a sculpture of crossed axial and spital ribs or riblets, not necessarily at right angles.

Lira: (Pl. lirae). A ridge on the shell surface within the aperture of a gastropod shell.

Lirate: With lirae.

Liration: DONT USE. USE Lirae.

Littoral: The zone of the shore between high and low tide levels.

Maculate: Patterned with regular or irregular patches. ie with maculations.

Mantle: The thin skin-like organ which covers the body mass of molluscs and contains the shell-secreting glands.

Mantle line: The line on the dorsal surface of a cowry shell where the mantle lobes meet.

Nacreous: With a layer of nacre, or mother-of-pearl.

Nodule: A rounded protuberance; larger than a bead.

Nodulose: Bearing rounded protuberances.

Oblique: Slanting; inclined from the horizontal or vertical.

Obsolete: Slight, barely apparent.

Operculum: The corneous or calcareous structure attached to the posterior end of the foot of many gastropod shells that closes the aperture when the animal withdraws into the shell.

Opisthocline: Refers to the slope of the outer lip of a gastropod shell sloping backwards in relation to the direction of shell growth.

Orthocline: Refers to the slope of the outer lip of a gastropod shell being parallel to the shell axis, not sloping forward (prosocline) or backwards (opisthocline).

Outer lip: The lip of the aperture of a gastropod shell furthest from the shell axis. The outer lip itself has inner and outer surfaces.

Papillate: Teat-like

Paratype: A specimen other than the holotype which was seen and designated by the author at the time of the original description of a species or subspecies.

Parietal: Pertaining to the parietal region.

Parietal shield: A calloused area found in some gastropod shells, covering the parietal wall.

Parietal wall: the region of a gastropod shell that extends from the columella around the top of the aperture to the outer lip.

Pelagic: Living on the surface of the sea or in the water column; opposite to benthic.

Penultimate: Second last.

Periostracum: Outer layers of horny material covering the calcareous shell. May be thin and transparent or thick, fibrous or hairy.

Periphery: The part of a gastropod shell farthest from the axis of coiling.

Peristome: The lips or margin of the aperture of a gastropod shell.

Plait: Spiral fold or ridge on the columella. Plica.

Planispiral: Coiled in a single plane.

Planktonic: Drifting or weakly swimming in the ocean.

Planktotrophic: Refers to planktonic larval development where the larvae feeds on micro-organisms and development time in the plankton is long.

Plica: (pl. plicae). A columellar fold.

Plicate: Folded or twisted; having plicae.

Porcellaineous: Polished; surface and texture as in porcelain.

Posterior: The tail end of an animal; in a gastropod shell, towards the apex .

Posterior canal: Anal canal.

Preoccupied: refers to a name which cannot  because it was used for another taxon, or was not validly introduced..

Primary: Of the first order; most dominant or conspicuous.

Proboscis: An extensible snout, usually with the mouth at its end.

Produced: Drawn out; elongated; extended.

Prosocline: Referring to the outer lip of a gastropod shell, leaning forward in relation to the direction of growth.

Protoconch: Embryonic shell, present in the adult as the apical or nuclear whorls and often demarcated from the teleoconch whorls by a change of sculpture.

Punctate: Minutely pitted.

Pustulose: With pimple-like or blister-like swellings

Recurved: With the end bent away from the shell axis.

Reflected: Turned outwards and backwards.

Reticulate: Lines, riblets, threads or grooves crossing each other like a net.

Rib: An elongate sculptural element of a shell, raised above the surrounding surface. A fine rib is a riblet, and a very fine rib is a thread.

Riblet: A small rib, but coarser than a thread.

Rugose: Rough; covered with wrinkles, folds or creases.

Scabrous: Covered with scales

Scale: Thin plate-like structures, more or less parallel to the shell surface, as in fish scales.

Secondary: Of the second order; less dominant or conspicuous than primary structures.

Serrate: Notched or toothed at the edge like a saw.

Shoulder: The region of each whorl of a gastropod shell showing a sharper angulation or greater convexity than the rest of the whorl.

Shouldered: Having a shoulder.

Sinistral: Coiled in a left-handed spiral. i.e. anticlockwise when viewed from the apex.

Sinuate: Curved in and out; wavy; tortuous.

Sinus: A deep indentation or cavity

Siphonal canal: An open or closed tubular shell extension at the anterior end of a shell through which the siphon is extended. Same as anterior canal.

Spatula: Spoon-shaped area at the centre of the interior of a limpet shell.

Spicule: A small, slender, needle-like spine.

Spinose: Bearing many spines.

Spiral sculpture: Sculpture following the helical growth of a gastropod shell.

Spire: All whorls of a spiral shell exclusive of the body whorl.

Stria: (Pl. striae). Narrow and shallow incised groove.

Striate: Marked with striae.

Subfossil: A fossil that is younger than what would be considered typical fossil age. i.e. preserved since about 10,000 years ago, but not strictly recent or present day.

Sublittoral: Below low tide level.

Subspecies: A geographically defined group of populations comprising individuals which possess characteristics distinguishing them from other such subdivisions of the species.

Substrate: The material of the sea bed.

Subsutural: Below (i.e. anterior to) the suture.

Suture: The continuous spiral line of junction of whorls of a gastropod shell.

Sympatric: ???????

Synonym: Each of two or more different names for the same species or other taxon.

Syntype: One of several type specimens where none has been designated as a holotype.

Teleoconch: All the whorls of a gastropod shell after the protoconch.

Tertiary: Of the third order; generally used for minor sculptural elements.

Thread: A very fine sculptural element of a shell, raised above the surrounding surface. Finer than a rib.

Top: In a gastropod shell, the posterior end.

Truncate: Cut off at the end, blunt.

Turreted: With the spire whorls like a succession of turrets, emerging one above the other.

Type locality: Locality at which the type specimen was collected.

Umbilicus: Cavity or hollow around the axis of a gastropod shell, formed when the inner walls of successive whorls do not meet.

Varical: Pertaining to a varix.

Varix: (Pl. varices). A thickened axial ridge in a gastropod shell, formed by thickening of the outer lip at a resting stage in the growth of the shell.

Ventral: Of, pertaining to, or situated on, the lower side of a dorsiventral organism; on the apertural surface of a gastropod shell. Opposite to dorsal.

Whorl: A single, complete turn of 360º in the spiral growth of a gastropod shell.