T. Gill establishes a subfamily of Triviidae around the genus Erato Risso: the Eratoinae (Arrangement of the families of mollusks, Washington 1871, p.9, item 107b. « The shells are mostly conical in outline, with the front terminal collar attenuated to a blunt end; adapically, the spire is almost always prominent rather than flattened; the outer lip angles away from the shell axis, whereas posteriorly it right-angles acutely back to the columella; outer lip is thickened, barely shouldered above; outer lip is denticulate, somewhat declivous toward the front; body whorl side margin is rounded, convex; the aperture, angling off to the rear, is broad and straight; the front terminal beak is broad and well defined; the posterior outlet is usually shallow or closed, although in a few species it may be clearly open. The columellar teeth may differ in width of interstices, size and shape tend to become less distinct, even obsolete adapically; always lacking are the bold, long, heavily formed plicae characteristic of the Marginellidae; there may be a weak, oblique ridge at the rear apertural canal; the fossular depression is very shallow or flattened, but narrow and distinct; the columellar base is rounded, convex, smooth; the outer shell surface is smooth, may be faintly glossy except for a few species that have granulations, wholly or in part, dorsally. » – C. N. Cate: “A review of the Eratoidae (Mollusca : Gastropoda)”, The veliger vol.19(3), Berkeley 1977, p.342.
 

« Shell cypraeiform, with a very developed and convex body whorl, the posterior ones convex often enveloped in the preceding; aperture lengthened, abruptly curved posteriorly; labrum thick, complete at right, denticulate or pleated. » – A. Risso: Histoire naturelle… vol.4, Paris 1826, p.240.
 

Shell granulose, with an aperture denticulate on both sides; apex obtuse; labrum thick.