The Collaborative International Dictionary of English v.0.48:
Equitably \Eq"ui*ta*bly\, adv. In an equitable manner; justly; as, the laws should be equitably administered. [1913 Webster]WordNet (r) 3.0 (2006):
equitably adv 1: in an equitable manner; "the inheritance was equitably divided among the sisters" [ant: inequitably]