- 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.
- A genus of chætopodous annelids, associated with the family members Hesionidæ.
- A genus of coleopterous pests.
- A genus of lepidopterous insects.
- (Salisbury, 1805.) In botany, see Nymphæa, 2.