5G): Oligospiral; exterior portion a calcareous disc, attached to an inner and slightly larger corneous layer; external surface off-white (usually encrusted with detritus particles), lacking colour pattern, but with a broad convex spiral ridge more or less at mid-whorl; thinner toward periphery; edge of disc concave, with numerous, close-set, rather unevenly spaced transverse partitions, except along the growing (parietal) margin, which is smooth.
Operculum: Oligospiral; exterior portion a calcareous disc, attached to an inner and slightly larger corneous layer; external surface very shallowly concave, lacking a distinct convex spiral ridge (cf.
4 length of propodi, each terminating in strong, curved corneous
unguis, flexor surface with about ten corneous
, distally curved, spinules arranged in three or four rows; propodi increasing in length from third to fifth, each with three or four spinules on ventrodistal margin and irregular two rows of spinules on ventral surface in third and fourth, with double row of spinules laterally and single row of sparse spinules mesially in fifth; carpi 0.
One corneous hepatic spine on each side of carapace.
Rostrum densely covered with punctations, excavated, strong median carina present; margins thickened, distal halves straight and slightly converging, terminating in rounded corneous spines, proximal halves slightly convex.
Can easily be recognized by the characteristic pattern of lighter, nontranslucent specks oriented in spiral lines on a darker, semi-translucent, corneous
background, as well as alternating zones of lighter and darker close-set axial riblets on the upper side of the shell with only microscopic spiral striation on the base.