Species of Hexagonalia
1. Hexagonalia brucei (Serène, 1973) (as Quadrella brucei) [type locality off Kenya; geographical distribution: western Indian Ocean] (Plate 4B)
2. Hexagonalia laboutei Galil, 1997 [known only from the type locality, Tuamotu Archipelago, French Polynesia]
A third species is being described from the Solomon Islands (Castro, in press).