Shell solid and highly glossy, with 4-5 slightly convex whorls, of which the ultimate one occupies 2/3 to 4/5 of the total height of the shell. A blunt, large, globular and glossy protoconch of about 1.5 whorls is present in most specimens and is almost never eroded. Columella strongly concave, parietal callus separated from the body wall, forming a deep and long false umbilicus, which almost splits the lower columella pillar into two. Suture not very well defined, but always visible. Anterior fasciolar groove deep and curved, fasciolar band divided into an anlerior and a posterior part, anterior fasciolar band slightly more raised than posterior fasciolar band and of a lighter colour. Posterior fasciolar groove relatively shallow. Ancillid band narrow but clearly present. Ancillid groove present, usually dividing the ancillid band into two. and ending in a small 1 a bra I denticle. Operculum chilinous, filling aperture completely. Genotype by monotypy: Buccinum glabratum Linnc, 1758.

The wide and pronounced false umbilicus is a feature unique among the Ancillinae. As Eburna is easily separated from other genera, and apparently has a very restricted geographic distribution, I do not consider Eburna to be a subgenus of Ancilla Lamarck, 1799, as many authors suggest. Petuch & Sargent (1986: 17) indicated the existance of six species in Eburna, but failed to indicate which. The genus Ancilla was thoroughly revised and discussed by Kilburn (1981). Amalda H. & A. Adams, 1852, with its type, the southern
Caribbean Ancillaria tankervillei Swainson, 1825, is very close to Eburna. The diagnostic characters of Amalda as given by most modern authors are not descriptive of its type, A. tankervillei, but fit those of some Indo-Pacific Baryspira species much better. Systematics of the subfamily Ancillinae are based upon a work of Chavan (1965), whose diagnosis of Amalda is a problematic one. Most of the diagnostic characters for Amalda as given by Chavan do not match Ancillaria tankervillei. Both schematic figures of Amalda as given by Chavan (1965: 105, fig. 8) and Kilburn (1977: 13, fig. 1) are clearly not drawn after a specimen of A. tankervillei but after an unidentifiable Baryspira species. The extensive secondary spire callus present in both above-mentioned figures is not found in A. tankervillei. In most specimens of A. tankervillei a tendency to form a false umbilicus can be observed. Moreover, it has the same type of glossy, bulbous protoconch as is found in Eburna, the same very typical orange colouration and the same structure and placement of the ancillid groove and ancillid band. I therefore consider Amalda a subgenus of Eburna and not a separate genus.The relationship between Eburna and the mainly Japanese and Indo-Pacific genera or subgenera Baryspira, Alocospira and Gracilispira, is not clean Recently many new species in these groups were discovered and described (see Kilburn & Bouchet, 1988; Ninomiya, 1987, 1988; Petuch, 1987; van Pel, 1989). Ancilla (Hesperancilla) matthewsi Burch & Burch (1967: 81-82) (PI. I figs. 13-14), an other southern Caribbean species, might also be related to Eburna. Kilburn (1981: 357) states the possibility that the Ancilla-like characters of A. matthewsi are convergent and that it is could actually be an offshoot of an Amalda or Eburna lineage. Its unusual crenulate ancillid groove might be a commenced development of the ancillid groove structure as observed in Eburna. According to Kilburn, possible precursors of A. matthewsi were Ancillaria lamellata Guppy, 1866 and Ancilla paralamellata Mansfield, 1925 from the Miocene of Trinidad. In turn these two species show a distinct phylogenetic resemblance to Eburna nitida Wanner & Hahn (1935: 246, PI. 18 fig. 1) from the lower Miocene of Java, Indonesia, which indeed seems to be an Eburna. Furthermore, it is worth noting that all above-discussed species share the same habitat in the southern Caribbean and have the same orange colour, occasionally being completely white.