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.

H

HEIGHT
Distance between the UMBO and the ventral margin.
HERMAPHRODITE (adj. HERMAPHRODITIC)
Sexually mature animal in which male and female gametes are produced by the same individual, either simultaneously or in sequence; see also PROTANDRIC.
HETERODONT
HETERODONT fig.HINGE type characterized by the presence of more than one type of HINGE TEETH (i.e., CARDINAL plus LATERAL TEETH); occurring in most Tertiary and Recent bivalves (figure: Polymesoda floridana).
HETEROMYARIAN
HETEROMYARIAN fig.With unequally sized ADDUCTOR MUSCLES; in most cases, the posterior adductor muscle is larger than the anterior; also called anisomyarian (figure: Pinnidae).
HETERORHABDIC
Gill type characterized by having more than one type of filament, producing a corrugated or plicate surface; see also HOMORHABDIC.
HINDGUT
HINDGUT fig.Posterior portion of the intestine, here applied to that part external and posterior to the visceral mass (figure: Corbiculidae).
HINGE
Collective term for the dorsal border of the articulated valves, including the LIGAMENT, HINGE TEETH, and other structures that function to permanently unite the two valves; also called hinge line.
HINGE LINE
See HINGE.
HINGE PLATE
The flattened interior dorsal area that bears the HINGE TEETH and LIGAMENT; called provinculum in larval bivalves.
HINGE TEETH
HINGE TEETH fig.A series of calcified dorsal interlocking teeth and sockets that allow alignment of the valves to be maintained during opening and closing; see also CYCLODONT, DESMODONT, DYSODONT, EDENTATE, HETERODONT, ISODONT, TAXODONT (figure: Laevicardium serratum). A tooth numbering system for heterodonts, originally proposed by Bernard (1895), labels hinge teeth according to their position and appearance during ontogeny as follows:
  • right anterior cardinal tooth: 3a
  • right middle cardinal tooth: 1
  • right posterior cardinal tooth: 3b
  • left anterior cardinal tooth: 2a
  • left middle cardinal tooth: 2b
  • left posterior cardinal tooth: 4b
  • anterior lateral teeth: left AII fitting between right AI and AIII
  • posterior lateral tooth: left PII fitting between right PI and PIII
HIRSUTE
Hairy, pertaining here to PERIOSTRACUM that consists of long, shaggy processes.
HOLOBRANCH
See CTENIDIUM.
HOLOTYPE
A unique specimen designated to represent the concept of a named species (currently always so designated by the original author in the original description); see also LECTOTYPE, PARATYPE, SYNTYPE.
HOMOGENOUS
Shell microstructural variety consisting of irregularly shaped but more-or-less equally sized aragonitic elements that show no regular arrangement.
HOMORHABDIC
Gill type characterized by having only one type of filament, thus unplicate or smooth; see also HETERORHABDIC.
HYALINE ORGANS
MANTLE structures occurring in the subfamily Tridacninae (Cardiidae), equipped with lenses, which transmit light to symbiotic ZOOXANTHELLAE in tissue.
HYOTE SPINES
Hollow tubular spines that are open distally and along the size, resulting in an ear-shaped opening; occurring in such families as Ostreidae and Gryphaeidae.
HYPOBRANCHIAL GLANDS
Glands in the SUPRABRANCHIAL CHAMBER of protobranch and a few other bivalves; in protobranchs, the glands function in the consolidation of waste material in the MANTLE CAVITY and in non-protobranchs, in the nutrition of larvae being incubated in the gills.
HYPOPLAX
HYPOPLAX fig.Accessory shell plate in Pholadidae and Teredinidae that covers the posteroventral margin (figure: Martesia striata).