The umbos are just behind the mid point and described as fairly narrow. The surface (periostracum) is slightly glossy and has coarse, irregular concentric striae.
In the context of shell morphology, the umbos are situated near the midpoint and are described as being fairly narrow in width. The outer layer (periostracum) has a subtle sheen and displays coarse, irregular striations that provide valuable information about the shell's texture and structure.