Pteriomorphia (mussels, scallops, oysters; phylum Mollusca, class Bivalvia) A subclass of bivalves, most of which are sedentary, epifaunal, and byssate or cemented. The most specialized genera have a reduced anterior adductor muscle and foot, and in some forms they are absent. The shells are variable in shape and composition; they may be aragonite, calcite, or both. They have a duplivincular ligament, unique to certain members of the subclass, and the dentition is variable. They first appeared in the Lower Ordovician.
More From encyclopedia.com
Nonarticulate lampshells , Inarticulata (Ecardines; phylum Brachiopoda) A class of brachiopods whose chitinophosphatic or calcareous valves are held together only by muscles an… Flat Foot , flat-foot·ed • adj. 1. having flat feet: a flat-footed, overweight cop. 2. having one's feet flat on the ground: he landed with a flat-footed thud |… Monoplacophorans , Monoplacophora (phylum Mollusca) A class of primitive, almost bilaterally symmetrical, univalved molluscs, whose limpet-shaped shell of calcium carbo… Goosefoot , goose·foot / ˈgoōsˌfoŏt/ • n. (pl. goosefoots ) a plant (genus Chenopodium, family Chenopodiaceae) of temperate regions with divided leaves that are… Foot , Attention to foot education and care is especially important as people age. The National Institute on Aging reports high prevalence of lower extremit… Feet , feet bipedalism, emerging about 3 million years ago, is considered to have been a crucial step in evolution, especially as it allowed the hand to dev…
About this article
Updated About encyclopedia.com content Print Article
You Might Also Like