Hedley proposed Exomilus for a group of very small southern Australian shells, sub¬cylindrical in shape, with few whorls, narrow aperture, the outer margin denticulate within. The sculpture is very coarse, consisting of strong axial ribs rendered clathrate by spiral cords. To which may be added that the protoconch in the genotype is short, greatly flattened and cap like, overhanging the first adult whorl. The sinus is shallow and subsutural.

The genus is an inhabitant of temperate waters and most of the species occur in South Australia and Tasmania.