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

by Paul S. Mikkelsen

Look for:  
Search results for:   MARGIN       22 terms were found.

Term Definition

MARGIN   [need definition].

ANTEROVENTRAL MARGIN   In bivalves, the anterior end of the valve margin opposite the hinge; See also: POSTEROVENTRAL MARGIN;

BASAL MARGIN   Edge of shell opposite hinge, in bivalves; = VENTRAL MARGIN.

CARDINAL MARGIN   The edge of a BIVALVE shell on which the HINGE TEETH are located.

COMMARGINAL   [need definition].

COMMARGINAL RIB   [need definition]; see also: OVERRIDE.

CONMARGINAL   Preferred term by some modern authors for structure with direction coinciding with that of growth lined; = CONCENTRIC, in bivalves.

EMARGINATE   Notched at the MARGIN.

HINGE MARGIN   Edge of bivalve shell that approximates most closely to hinge axis.

INFRAMARGINAL   Situated below a MARGIN.

MARGIN   The free edge, generally of a sculptural element; the edge of the aperture. See: CARDINAL MARGIN; MARGIN, DISCORDANT.

MARGIN, DISCORDANT   With margins of closed valves not in exact juxtaposition, but one overlapping the other; example: Anadara; see also: INEQUIVALVE.

MARGINAL   Located on the margin, or near the edge; see also: TOOTH, MARGINAL"/a>.

MARGINAL CARINA   Ridge in Trigoniacea (Bivalvia) that runs from UMBO to posteroventral angle of shell and delimits posterior area.

MARGINAL TOOTH   Those teeth of a RADULA, which lie to the outside of the LATERAL TEETH; see also: RACHIDIAN; RADULA FORMULA.

MARGINATE   Having an edge or border thicker than the rest of the shell (as in the genus Marginella); see also: EMARGINATE; INCRASSATE.


POSTERODORSAL MARGIN   In bivalves, the margin of the DORSAL part of the shell POSTERIOR to the BEAKS.

POSTEROVENTRAL MARGIN   In bivalves, the posterior end of the valve margin opposite the hinge; = POSTEROBASAL MARGIN. See also: ANTEROVENTRAL MARGIN;

SHOULDER MARGIN   The periphery or outermost edge of a WHORL.

SUBMARGIN   One of the dorsal edges of the disk or body of a shell in the Pectinacea, adjoining the lower body of the AURICLE.

VARICAL MARGIN   The free, often sculptured, generally SERRATE or CRENULATE edge of a VARIX.

Copyright ©Paul S. Mikkelsen, All Rights Reserved Return to Home Page  |  Return to Top Over 1700 Terms in the Glossary!