Shell pure white, with a straw-colored nucleus, ten-whorled. Spire rather acute, whorls obliquely smoothed off in front of the sutures. Nucleus four-whorled, above smooth, below sculptured with semilunar transverse ripples and a basal carina; spiral sculpture of very fine spiral threads, lightly decussated by wavy lines of growth; there are also two strong threads near the periphery, one lower which is obscured by the suture, and on the last whorl three, more anterior, beside the usual spiral sculpture of the canal; these strong threads become much more prominent, stronger, and sharply keeled, as they pass over the transverse riblets; transverse sculpture of eight rounded ribs, which appear near the periphery and extend over it on to the base; they are crossed by the spiral sculpture; suture appressed, wavy ; the absence of ribs near the suture and the flattening of the shell there give this species a somewhat Pleurotomoid aspect, but there is no notch; canal moderate, strongly twisted ; aperture smooth within, edges sharp, simple. Max. lon. of shell, 17.0 mm; of last whorl, 10.3 mm; of aperture and canal, 8.0 mm; max. lat. of shell, 6.6 mm.

Shell slender, rather small (up to 24.5 mm), variable in shape, consisting of ten angulated whorls, spire acute, pure white. Protoconch straw-coloured, 3 1/2 whorls, untypical for genus; upper part smooth, below sculptured with semilunar axial riblets and a basal carina. Diameter: 0.8 mm.
About eight rounded, rather strong axial ribs per whorl, which are most prominent at the periphery; they terminate below the upper suture on latter whorls.
Three strong spiral cords, the lowermost one is lying in the lower suture, the two central ones giving the whorls a bicarinate appearance with a flat almost unsculptured shoulder. These strong cords become more prominent and sharper where they pass over the axial ribs. Many very fine intercalated spiral threads between the three strong cords crossed by fine growth lines.
Aperture nearly round, smooth within, with sharp lips. Siphonal canal short, strongly-twisted.

The nucleus of this little shell is peculiar, and the aperture is imperfect, but it is clearly different from any of the known species. There is something in the texture of the shell and the finer sculpture which recalls Sipho glyptus Verrill.

F. amiantus belongs perhaps to another genus because the morphology of protoconch and radula is not typical for the genus Fusinus (both figured by BOUCHET & WAR£N, 1985): The central tooth of the radula has only one single cusp instead of usually 3 or sometimes 4 cusps.
Also the protoconch is clearly different: usually about 1-1,5 whorls, of which 3/4 - 1 1/4 whorls smooth, final part with axial riblets. Sometimes the whole protoconch is strongly plicated (e.g. subgenus Heilprinia). We prefer not to change the genus without study of the higher taxa.

Gulf of Mexico (off Havana). Caribbic area and continental slopes of the Azores.
Type locality: F. amiantus: off Havanna, Morro Light, Cuba (23°14,00"N,82°25I00"W), U.S. Coast Survey St. 2, 1480 m.
F. grimaldii; Azores, Monaco St. 213 (39023'N,31Q25,W), 1384 m.
Af. decorata: Azores, Talisman 1883 dr 127 (38Q38,N,28U21,W), 1257 m.