Shell small, variable in size, 3 to 6,5 mm in length and from 1,3 to 2,5 mm width. Costate to nearly smooth and rather solid. Whorls 3,5 to 4,5 and rather strongly convex. Color pale straw-yellow to red-brown with a white lip. Spire lengthened and truncated. Suture rather deeply impressed. Aperture holostomatous, subcircular to subovate. Parietal wall thickened with the inner lip extending above. Outer lip duplex with the lower lip very much thickened. Basal ridge short, thickened and merging into the lower lip. Shell imperforate or at best with a very minute rimation. Columella not apparent. Sculpture generally consisting of numerous well formed axial ribs which extend from suture to suture. Many specimens, however, have the sculpture much reduced, consisting only of very short riblets which appear only above and below the suture, the peripheral area being quite smooth and shiny. All grades of sculpture from those that are nearly smooth to those that are strongly costate may exist in specimens from a single locality. Operculum paucispiral, corneous and generally with a thin calcified plate on the outer face. In young specimens the first two whorls are smooth, the third whorl finely costate and the remaining whorls increasingly so.

We are unable to separate Truncatella bairdiana Adams, from the Pacific at Panama, from T. bilabiata Pfeiffer. Just why Adams compared his new form with T. scalariformis Reeve of Polynesia instead of T. bilabiata Pfeiffer of the West Indies is a little difficult to understand. T. scalariformis is a very different species and in no way related to the Panamanian form. T. bilabiata possesses a well developed duplex lip and a strongly developed basal ridge, characters which readily separate it from T. pulchella. We have seen three cotype series of T. capillacea Pfeiffer. Two of these lots (MGZ) consist of depauperate specimens of T. bilabiata Pfeiffer while the third is made up (USNM) of depauperate specimens of both T. bilabiata Pfeiffer and T. scalaris Michaud. The type locality, Caimanera, Cuba, near the Guantanamo Naval Base is in Guantanamo Harbor and at a considerable distance from the harbor entrance. Habitat conditions at this place are probably not very favorable for their existence.

Florida and the West Indies south to Trinidad, Lesser Antilles. Also the Eastern Atlantic at Morocco and the Madeira Islands and the Eastern Pacific at Panama. It is quite possible that T. bilabiata is adventitious in the Eastern Atlantic. It is exceedingly common in the West Indian region and distribution from this area eastward to Madeira and the adjacent coast of Africa is not impossible.