n. A genus of bivalve mollusks, of the family Iridinidæ, confined to the fresh waters of South America. The best-known species is C. ambigua. The genus was founded by Lamarck in 1819.n. A genus of chætopodous annelids, of the family Hesionidæ.n. A genus of coleopterous insects.n. A genus of lepidopterous insects.n. (Salisbury, 1805.) In botany, see Nymphæa, 2.