( n. )
A genus of bivalve shells of which one species (D. polymorpha) is often so abundant as to be very troublesome in the fresh waters of Europe.
( n. )
A genus of bivalve shells of which one species (D. polymorpha) is often so abundant as to be very troublesome in the fresh waters of Europe.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012