DIAGNOSIS: A Columbarium with a gradate spire and posteriorly directed keel spikes; posterior whorl slope flat with three spiral cords, anterior whorl slope with four spiral cords, the anterior carina and four spiral cords between it and the canal. Body whorl with four axial costae near the aperture.
DESCRIPTION : Shell gradate, prominently shouldered with rather coarsely corded spire whorls; keel with 12 posteriorly directed spikes on the last whorl, the bases of which bear four fine scaly threads set en echelon. Posterior whorl slope with three spiral cords, anterior whorl slope with three spiral cords between keel and anterior carina and four further cords between it and the canal. All cords scabrose due to the crossing of the growth lines. Last third of body whorl with four broad costae coincident with the spikes of the keel. Aperture subcircular. Canal elongate, very slightly twisted and bearing five spiral lirae.

Distinguished from other species of the genus by its lack of spines apart from those of the keel, the wrinkled appearance of the surface of the shell and by the presence of the four broad axial costae on the last third of the body whorl. These axial costae may be due to an accident during growth as they are quite out of harmony with the rest of the shell. The spire whorls are slightly offset giving the spire a crooked appearance which may support this view. Further specimens are required to settle this question.
The only other species of Columbarium which approaches C. natalense is C. distephanotis Melvill from Torres Strait, N. Australia, but that species has well developed costae on all whorls except the first three, and has a prominent nodulose cord between the keel and the anterior carina.
A similar development of lirae on the keel spikes is seen in Columbarium acanthostephes (Tate).

LOCATION OF TYPE: South African Museum: SAM A3497, Pieter Faure Collection.
TYPE LOCALITY: Off Cape Natal, WIN, 12 miles, 85 fathoms, Durban, S. Africa.