Shell moderately small (8-12 mm), claviform with high spire, blunt apex and short, contracted base, aperture small, somewhat quadrate, except for the short, spout-like, unnotched siphonal canal, no fasciole; labrum thin, with very shallow to deep, openly U-shaped anal sinus, no stromboid notch or parietal callus pad; whorls without subsutural cord or sulcus, shoulder slope sometimes gently concave: sculptured by spiral cords and weak peripheral axial ribs. Protoconch large, of about 2,5 whorls, tip smooth or with two low spiral cords, rest with strong axial ribs. Operculum, radula and soft parts unknown.

Pseudexomilus was based on a species from the Pliocene of South Australia, characterised by its somewhat terebriform shape and large, axially ribbed protoconch. Subsequently. Powell (1966:137) referred here also the Recent South Australian Drillia costicapitata Vcrco. 1909). He regarded the genus as a member of the subfamily Daphnellinae [ = Raphitominae], but the growth-lines visible in the type figures of both P. caelatus (Powell. 1944: pl. 6. Fig. 12) and P. costicapitata (Verco, 1909: pl. 27, Fig. 1) appear to show an anal sinus that is possibly mangeliine but more probably 'clavine’. In the new South African species, here described, the anal sinus forms a deep embayment with its rounded apex on the mid shoulder-slope, and in the fourth known member of the genus. P. bicarinata Shuto. 1983. from Queensland, the sinus is similar but very shallow. Despite the absence of a parietal pad I suspect Pseudexomilus to be a clavine genus. The axially ribbed protoconch is probably indicative of subfamily Crassispirinae. although radula evidence is required.