Unionidae definitions

Unionidae

1) Family unionidae 2) Mollusk family
Found on https://www.crosswordclues.com/clue/unionidae

The Unionidae are a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, or simply as unionids. The range of distribution for this family is world-wide. It is at its most diverse in North America, with about 297 recognised taxa, but China and Southeast Asia also support very diver...
Found on http://en.wikipedia.org/wiki/Unionidae

Unionidae

(from the article `conservation`) ...are far from being the only places where recent extinctions have occurred. The Mississippi and St. Lawrence river basins were home to 297 North ... ...may be important also in the bioerosion of corals. Bivalves thus occur at all latitudes and depths, although none are planktonic. There are also ... ...
Found on http://www.britannica.com/eb/a-z/u/9

Unionidae

Unionidae is the Fresh-Warerr Mussels family of bivalve molluscs. The two valves of the shell are equal and sometimes very thick, with pearly inner lining, the foot large and thick, and the byssus or attaching threads absent. They occur in rivers and lakes in all parts of the world. In Great Britain four species occur ; Unio tumidus and Unio pictor...
Found on http://www.probertencyclopaedia.com/browse/BU.HTM