Type of wall: Finely perforate with pores averaging 1.9 mm and ranging from 1.1–2.4 mm, wall surface with randomly scattered, fine muricae.

 Test morphology: Test planispirally coiled, biumbilicate, moderately evolute with a relatively broad, shallow umbilicus (U_D:T_D ratio average 0.31), equatorial outline weakly lobate, subcircular in peripheral outline with a rounded to subrounded peripheral margin, symmetrical in edge view, always biapertural; chambers weakly inflated, enlarging very slowly in size (y = 0.092x + 1.77) with uniform, log-linear growth throughout ontogeny (text-figs. 4a, 4e, 6), 22–23 total chambers in adult specimens usually coiled in 2.5 whorls (e.g., Pl. 21, Figs. 1c, 2c, 5c), average of 7.7 chambers and range of 7.0–8.5 chambers in the final whorl (Table 1), kummerform chambers rare (U_CL:P_CL ratio average 1.0); sutures slightly curved, weakly depressed; final chamber biapertural with a low arch or slit opening into the umbilicus, may show inward flexure along suture (Pl. 21, Figs. 1a, 3a, 5a, 6a, 8, 9a), bordered by a narrow, imperforate flap that extends into the umbilicus connecting with previous chambers, and may become outwardly folded and tubular shaped (e.g., Pl. 21, Figs. 1a, 3a, 5a, 6a, 11); relict apertures and apertural flaps visible surrounding the umbilicus.

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