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

by Paul S. Mikkelsen

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Term Definition

AURIFORM   Shaped like a human ear; used in describing the rhinophores of Hermaea spp.; see also: AURICULATE; HALIOTOID.

AVICULIFORM   [need definition].

CARDINAL PLATFORM   Shelly internal plate bearing hinge teeth, situated below beak and adjacent parts of dorsal margins and lying in plane parallel to that of commissure; = HINGE PLATE.

CORBULIFORM   Shaped like the shells of the bivalve genus Corbula.

CORDIFORM   Heart shaped, as in the bivalve Corculum cardissa. See also: CORDATE.

CUNEIFORM   Wedge-shaped.

CYATHIFORM   Cup-shaped (as in the "cup" of "cup and saucer" limpets, the Calyptraeidae).

CYPRAEIFORM   A shape exemplified by the gastropod genus Cypraea. See other gastropod shapes.


DONACIFORM   A form of TRIGONAL shape exemplified by the BIVALVE genus Donax. See other bivalve shapes.

ECOLOGIC FORM   A morphological condition brought about by the influence of the environment, such as long SPINES in quiet waters; also called: ECOTYPE or ECOPHENOTYPE. See also: FORM or FORMA

ENSIFORM   An ELONGATE bivalve shape, like an Ensis; with outline resembling a curved sword. See other bivalve shapes.

FALCIFORM   Sickle-shaped.

FLABELLIFORM   Fan-shaped.

FORM or FORMA   A minor genetic variant, color phase, aberration, or variation due to diet or environment (e.g., an ECOLOGIC FORM); see also: ECOPHENOTYPE; ECOPHENOTYPIC VARIATION; ECOTYPE; VARIETY.

FUSIFORM   Spindle-shaped; biconic, i.e., swelling in the central part and tapering at the extremities.
See other gastropod shapes.

HAMIFORM   Curved at the extremity; see also: FLEXUOUS; RECURVED; REFLECTED.

HELICIFORM   Shaped like shells of the genus Helix. See also: ESCARGOT. See other gastropod shapes.

INFUNDIBULIFORM   Funnel-shaped, as in the siphon or funnel of a CEPHALOPOD.

LIMACIFORM   [need definition]; used by Abbott, 1974 (pg. 367) in description of Dendronotus.

LINGUIFORM   Tongue-shaped. See also: ELONGATE

LOBIFORM   Lobe-shaped.

MODIOLIFORM   Shaped like the shell of Modiolus spp.; differing from MYTILIFORM in that the BEAKS are not quite terminal and ANTEROVENTRAL region forms slight bulge.

MONILIFORM   Composed of a row of beads, like a necklace; see also: BEADED.

MUSCLE SCAR, CRUCIFORM   [need definition].

MYTILIFORM   Shaped like the shell of the genus Mytilus. See other bivalve shapes.
Photo: Modiolus modiolus (Linne, 1758)

NERITIFORM   A GLOBOSE GASTROPOD shape resembling that of a Nerite snail (e.g., Nerita spp.; Neritina spp.): with few subglobose and rapidly enlarging whorls with a very reduced SPIRE. See other gastropod shapes.

NUCULANIFORM   A shape exemplified by the bivalve genus Nuculana; = ROSTRATE. See other bivalve shapes.

PATELLIFORM   Shaped like a human knee cap or patella; = PATELLATE. See other gastropod shapes.

PECTINIFORM   [need definition].
Photo: Argopecten irradians concentricus (Say, 1822)

PTERIIFORM   A shape exemplified by the bivalve genus Pteria. See other bivalve shapes.
Photo: Pteria colymbus (Roding, 1798)

PUPIFORM   Shaped like members of the genus Pupilla [Pupillidae]. See other gastropod shapes.

PYRIFORM   Shaped like a pear.

RADULA FORMULA   A series of numbers indicating the number of MARGINAL TEETH, LATERAL TEETH and the RACHIDIAN TOOTH, and (again) the lateral teeth and marginals.
Example: a formula of 3+6+R+6+3 indicates 3 marginal teeth, 6 lateral teeth and 1 rachidian (R) tooth. The radula formula may be simply "1" if the radula is UNISERIATE, having only rachidian teeth. See also: DOCOGLOSSATE; STENOGLOSSATE; RHIPIDOOGLOSSATE; TAENIOGLOSSATE; TOXOGLOSSATE.

See the excellent illustrations on Wikipedia.

RENIFORM   Shaped like a kidney (e.g., the aperture of Ampullaria spp.).

SCALARIFORM   Loosely coiled; see also: TIGHTLY COILED.

SECURIFORM   Hatchet-shaped.


TEREDINIFORM   A shape exemplified by the SHIPWORM bivalve genus Teredo. See other bivalve shapes.
Illustration: Teredo sp. (left = entire animal; center = PALLETS; right = shell)

TRAPEZIFORM   With four straight sides, only two of which are parallel; see also: POLYGONAL; QUADRATE.

  Having the form of a top; conical, with the base of the cone at the APERTURE; see also: TURBINATE. See other gastropod shapes.

TURRIFORM   Tower-shaped; = TURRICULATE. See other gastropod shapes.

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