Falcidens is one of three genera within the family Chaetodermatida; its radula consists of a single row of teeth which are mineralized in crystalline hydroxyapatite (a most unusual mineral in organisms), and its teeth are not periodically shed and replaced like in other molluscs.

[2] For details of the radula, see Radula#In caudofoveates.

It contains the following species:[3]