Glossary

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The glossary provided here is largely based on “Seashells of Southern Florida: Bivalves,” by Paula M. Mikkelsen & Rüdiger Bieler, Princeton University Press. Production of this glossary was funded in part by the National Science Foundation’s Partnerships in Enhancing Expertise in Taxonomy [PEET] Program, NSF-DEB-9978119, “Bivalves - Research, Training, Electronic Dissemination of Data” (1999-2008) to Bieler and Mikkelsen.

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RADIAL
RADIAL fig.Referring to external sculptural features that originate at the UMBONES and fan outward toward the margins (figure: Carditamera floridana).
RECTUM
End portion of the intestine; either sessile (laying appressed to the posterior adductor muscle) or freely hanging.
RESILIAL TEETH
Elevated ridges on a resilifer.
RESILIFER
RESILIFER fig.Structure (often a flat or recessed trigonal platform) on each valve, supporting the internal LIGAMENT or RESILIUM; also called ligamental pit; see also CHONDROPHORE (figure: Semele proficua).
RESILIUM (pl. RESILIA)
RESILIUM (pl. RESILIA) fig.Pyramidal enlargement of the LIGAMENT ventral to the HINGE line; also called internal ligament (figure: Spisula similis).
RETICULATE
See CANCELLATE.
RIB
An elongated sculptural element that is raised above the surrounding shell surface; a very fine rib is often called a riblet or thread; also called ridge; see also GROOVE, STRIA.
RIBLET
See RIB.
RIDGE
See RIB.
ROSTRUM (adj. ROSTRATE)
ROSTRUM (adj. ROSTRATE) fig.Elongated or drawn-out posterior extension of a shell, usually enclosing the SIPHONS (figure: Cuspidaria rostrata).