wedge shell (or wedge clam, or coquina) are any of a large number of species of the genus Donax, small but edible marine bivalves. The hinged, double shell is wedge shaped and small, and the creatures are best used to make a clam broth. Donax trunculus is the main Mediterranean species, and has been extensively consumed in certain regions, for example around the mouth of the Nile. D. californicus is gathered, without great enthusiasm, on the Californian coast. Another Californian species, D. gouldi, is more popular and has been abundant in some years; its shell has a slightly different shape which earns it the name bean clam (cf. the French name haricot de mer for D. trunculus).