Shell broadly fusiform, small (to 16.7 mm), with up to 9,5 whorls, approximately 64% of the total length occupied by the last whorl, giving the shell a squat appearance. Shell surface glossy. Protoconch of approximately 1,75—2 smooth round whorls. Axial sculpture of broad round ribs that stretch from suture-to-suture on spire whorls, and evanesce on the shell base; usually 5 per whorl, but occasionally 6-7 on the penultimate or as few as 4 on the body whorl. Interspaces wider than ribs. The five ribs give a pentagonal shape to the whorls in cross section. Ribs almost always align whorl-to-whorl. Varix usually a thickened last rib, rarely the penultimate, approximately 1/4 to 1/3-whorl from the edge of the outer lip. Spiral sculpture of fine spiral incised lines made jagged by microscopic growth striae, becoming heavier, thread-like, anteriorly on shell base; spiral threads on anterior fasciole. Sulcus is obscure, ill defined; usually only a slight reduction in rib height in the sulcal area, but sometimes marked by a slight inflection of the crest of the ribs. Outer lip thin, straight, the edge forming a low arc from the sulcus to the tip of the anterior canal. Stromboid notch obsolete. Anal sinus a slight invagination of the outer lip below the suture with a low callus on the parietal wall; on older specimens, inside edge of outer lip thickens forming a distinct channel. Inner lip is thin to thick, depending on the age of the specimen, slightly erect anteriorly but otherwise recumbent; a low callus present at its junction with the outer lip. Anterior canal short, but distinct, open, with a notch at its tip. Color white with two yellowish-brown spiral bands or a single broad band on ribs that vary in width and color intensity; some with a continuous band that is lighter in color between the ribs than on rib crests.

. The average length of 89 specimens is 8.41 mm (5.2-16.7 mm), and the average W/L ratio is 0.449. The color pattern varies; the wide central brown spiral band that colors the ribs may be entire, or broken into two narrower bands. Both color patterns are illustrated in Plate 12. No consistent geographic (E Florida versus W Florida) difference has been observed in the limited sample examined. The two-banded pattern is more common; the single wide band has only been observed in the eastern Gulf of Mexico, and specimens from the western Gulf are very pale. Six- and seven-sided forms are also occasionally encountered (see Plate 11, Figs. 19, 20). Identification. This species is easily recognized by its pentagonal shape in apical view, from the five ribs/whorl, and color pattern. It is closest to B. aurantiaca and to B. amplicostata, new species. It differs from B. aurantiaca in possessing a glossy shell (spiral microsculpture more subdued) and a different color pattern (yellowish brown bands on rib crests versus a continuous brownish-orange band that may be paler on rib crests). From B. amplicostata it differs in having fewer ribs (5 versus 7), and a different color pattern (yellowish brown bands on rib crests versus light creamy brown in intercostal spaces).

North Carolina; E Florida; Florida Keys; W Florida; off Louisiana; Mexico (Campeche Bank off Campeche); French Guiana. The report of this species off Amapa, Brazil by Rios, if true, would extend the range southward. Most frequently reported from moderately deep water in the range of 25-128 m; however, specimens have been reported from as shallow as 3 m and as deep as 457 m.