A glossy cylindrical snail that ploughs below the sand surface, leaving a raised trail.
A smooth cylindrical shell with a short spire and a long narrow aperture running most of its length, to about 7 cm, highly polished and patterned in fine zigzags, chevrons and blotches of brown, grey, violet and cream. The polish is not an artefact of collecting: in life the lobes of the mantle and the foot fold up over the shell almost completely, so the surface is rarely exposed to abrasion or to settling growth.
The animal ploughs through the top centimetre or two of sediment rather than over it, and the sign of one is a raised trail crossing the sand and ending in a slight mound where the animal is. It takes bivalves, small crustaceans and carrion, wrapping prey in the foot and carrying it down below the surface to feed. Numbers come up onto the surface after dark, and a piece of carrion on open sand will gather olives along with nassariids.
The confusion is with those nassariids, which share the ground and the behaviour but have a shorter, sculptured, matt shell, and with cone shells, which are the animals on this ground that carry a venomous harpoon. An olive has neither the sculpture of the one nor the sharp shoulder and slit-like aperture of the other. Recorded from the shallows to about 25 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.