coup de grÃ¢ce in British English. See all translations. coup de grÃ¢cenoun [ S ] uk â /ËkuË dÉ ËÉ¡rÉËs/ us â /ËkuË dÉ ËÉ¡rÉËs/ formal. âº an action that ends something that has been gradually getting worse, or that kills a person or animal in order to end their suffering: Jane's affair was the coup de grÃ¢ce to her disintegrating marriage. Thesaurus: synonyms and related words.
Bivalves is a class of marine and freshwater molluscs with about 30,000 species including scallops, clams, oysters, razor shells, shipworms and mussels. Most bivalves are marine usually found in shallower water but some live in brackish and freshwater.
Bivalve molluscs are so-called because their shell is divided into two articulated valves (compare them to gastropods and cephalopods, which are also molluscs). In large bivalves, such as scallops and large clams, the valves are corrugated to give them extra mechanical strength. Most bivalves are not capable of active swimming and most are burrowing animals, using their muscular foot to excavate a burrow in soft sediments (some bore into corals and similar hard materials).