Most adults have shells which are 20 to 50 mm (or about an inch, to an inch and three quarters) in diameter. Adults weigh anywhere from 2 to 20 grams. Individuals can live anywhere from 7 to 30 years; studies have shown that individuals inhabiting the more northern portions of the organism's range are larger and live longer on average than organisms inhabiting the southern portions.
In 1971, a new sense organ was discovered in this marine snail. Chemoreceptor organs were found near the base on the border of the leaflets of the ctenidium (comb-like respiratory gills), one on each leaflet. They form a light swelling near the base of the leaflet with a pocket lying within the swelling. Together they are termed a "bursicle".
Black turban snails living in a rocky intertidal zone