(
this section compiled from ) Shell of oval shape, with relatively low and blunt
spire and a large
body whorl. The shell is smooth and shiny. The
suture is open. The
aperture is elongate. The inner lip (= the inner border of the aperture) is covered by very thick
parietal callus that in mature animals extends beyond the aperture to the suture, where it may form a knob causing a pronounced kink in the outline of the shell in apertural view. Lirae (= ridges or plications) on the inner lip are lacking. The ground color is a dark brown or olive with a varying number (0 to 3) of lighter or darker, often fading bands. The fasciolar band (= a distinctly structured portion of the shell around the
siphonal notch) is brownish gray to white. A chitinous (= horny)
operculum is present. The living animal is brownish gray with characteristic dark marks on the propodium, the front part of the foot. It lacks cephalic tentacles and eyes. As in all
Olivellidae and the closely related
Olividae, the propodium is separated by a pronounced groove from the main foot, the metapodium. In
O. columellaris (as well as in
O. semistriata), the lateral tips of the propodium are greatly extended and function in
suspension feeding. The propodium is further divided into a left and a right half. The mouth opening which can be everted on a
proboscis, is located on the
dorsal face of the foot between the left and right
lobes of the propodium. ==Distribution==