An Illustrated and Cross-Referenced Glossary of
Malacological and Conchological Terms

by Paul S. Mikkelsen

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Term Definition

ADULT WHORLS   All whorls of a GASTROPOD shell beyond those of the nucleus, or PROTOCONCH; = TELEOCONCH; see also: NUCLEAR WHORL; PROTOCONCH.

BODY WHORL   The most recently formed WHORL of a gastropod shell, usually enclosing most of the animal's body.
See illustration of Composite Gastropod.

EMBRYONIC WHORL   A single WHORL of the NUCLEUS or PROTOCONCH; the earliest portion of the LARVAL SHELL.

NUCLEAR WHORL   The early larval shell, sometimes distinguished from the PROTOCONCH. See illustration: Composite Gastropod. See also: ADULT WHORLS; VELICONCH.

PENULTIMATE WHORL   The next to the last WHORL, or the one before the BODY WHORL (of snails).

PERIPHERY, WHORL   [need definition].

POSTNUCLEAR WHORL   Any turn of a GASTROPOD shell formed after the formation of the NUCLEUS.

PRECEDING WHORL   The turn of a GASTROPOD shell just previous to the one being described.

SPIRE WHORL   One turn (360 degrees) of the spire, exclusive of the BODY WHORL.

WHORL   A single complete turn of 360 degrees in the spiral growth of a gastropod shell or OPERCULUM; see also: BODY WHORL; PENULTIMATE; PERIPHERY, (types); WHORL, (types); VOLUTION.

WHORL PERIPHERY   The part of a GASTROPOD shell that is farthest from the AXIS of coiling; = WHORL PERIPHERY. See illustration: Composite Gastropod. See also: PERIPHERY, (types); WHORL, (types).

WHORL, ANGULATE   Having the outer PERIPHERY of the whorl midway between CARINATE and rounded.

WHORL, BICARINATE   Having two CARINA on the PERIPHERY of a whorl.

WHORL, CARINATE   Having one or more CARINA on the PERIPHERY of a whorl; see also: WHORL, BICARINATE; WHORL, MONOCARINATE.

WHORL, CONVOLUTE   Having the body WHORL of the shell expand abruptly so as to wrap around and conceal all the older, subsequent whorls as in Cyprea spp..

WHORL, DESCENDING   The lowering of the last stages of growth of the BODY WHORL.

WHORL, DISCONTIGUOUS   Having subsequent WHORLS not touching the previous; = WHORL, DISJUNCT; = GYROCONIC.

WHORL, DISJUNCT   Having subsequent WHORLS not touching the previous; = DISCONTIGUOUS; = GYROCONIC; see also: LOOSELY COILED. See other gastropod shapes.

WHORL, FLATTENED   The condition of having the PERIPHERY of a whorl being flat.

WHORL, HALF   Half of a full turn in the shell spiral of a gastropod; 180 degrees of shell growth.

WHORL, MONOCARINATE   Having a single CARINA on the PERIPHERY of a whorl; see also: WHORL, BICARINATE.

WHORL, ROUNDED   Having a smooth curve on the outer PERIPHERY of a whorl.

WHORL, SHOULDERED   Having an angulation of the whorl at its PERIPHERY or outermost edge.

WHORL, SUCCEEDING   A whorl later in the growth sequence and usually larger than the WHORL in question.

WHORLS, NUMBER OF   The count of revolutions of a shell or of an OPERCULUM.

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