The shell is moderate to large, fragile and globular in shape. It features a very large aperture and a low spire. The surface is sculpted with well-developed, broad, flat-topped spiral cords, and the base has a pronounced siphonal notch. Adult animals lack an operculum. This species is highly variable, with both shallow- and deep-water forms. On the Agulhas Bank, shells tend to be more globular, with a lower spire, a pronounced shoulder, and a slightly sunken suture. [3]
The color of fresh shells is light brown to orange-brown. The ribs are marked with irregular white blotches, bordered by darker brown bars. [3]
Distribution
This marine species occurs off South Africa, off the Agulhas Bank and East coast at depths between 50 m and 100 m; also off Madagascar.
Hanley, S. (1860a), Descriptions of New Univalve Shells from the Collections of H. Cuming and Sylvanus Hanley. Proceedings of the Zoological Society of London, 1859 27: 429-431
Bayer, Ch. (1937) Catalogue of the Doliidae in the Rijksmuseum van Natuurlijke Historie. Overgedrukt uit Zoologiscshe Mededelingen XX, Leiden, E. J. Brill, page(s): 38
Kilias, R. (1962) Das Tierreich, Lieferung 77, Gastropoda / Prosobranchia: 1-63, Walter de Gruyter & Co., Berlin. page(s): 35
Kilburn R.N. (1971). On some species of the families Tonnidae, Hipponicidae, Buccinidae, Columbariidae, Fasciolariidae, Psammobiidae and Mactridae (Mollusca) in South African waters. Annals of the Natal Museum 20(3):483-497
Steyn, D.G. & Lussi, M. (1998) Marine Shells of South Africa. An Illustrated Collector's Guide to Beached Shells. Ekogilde Publishers, Hartebeespoort, South Africa, ii + 264 pp. page(s): 70
Vos, C. (1999) A new Tonna Brünnich, 1772 (Gastropoda: Tonnidae) from Gulf of Aden. Gloria Maris, Vol. 38, (1–6), p. 43–47, pl. 8-9 page(s): 44
Vos, C. (2007) A conchological Iconography (No. 13) - The family Tonnidae. 123 pp., 30 numb. plus 41 (1 col.) un-numb. text-figs, 33 maps., 63 col. pls, Conchbooks, Germany page(s): 93