Norris's Topsnail

Norrisia norrisii

Norris's Topsnail is a medium-sized marine snail with a solid, smooth shell that can reach a maximum diameter of 59 mm. The shell typically displays a brown or reddish fawn color, along with light growth lines and subtle spiral markings. It features a low, conical spire and a rounded-quadrangular opening that is iridescent on the inside. The fleshy foot is bright reddish orange with black speckling, and the snail is recognized by its dextrally coiled, globular shape. It can be identified from similar species by its distinctive coloration and shell characteristics, including a smooth, green columella and an open umbilicus with a black ring. Empty shells are frequently used by hermit crabs for shelter. This species inhabits the Pacific coast of North America, ranging from Monterey to Isla Asuncion in Baja California, Mexico. Norris's Topsnail is typically found in the lower rocky intertidal zone and shallow subtidal regions, especially in kelp forests where it feeds on algae and microscopic films. It is often seen moving along the stipes of giant kelp, Macrocystis pyrifera, and is usually located at depths shallower than 40 meters, with most sightings occurring at depths less than 10 meters. Feeding mainly on kelps, Norris's Topsnail shows a preference for species such as Egregia and Laminaria. While details about its reproduction are limited, it is thought that, like many marine snails, it may reproduce through either broadcast spawning or internal fertilization. Its predators include sea otters, starfish, and lobsters, which makes it important for the snail to quickly detach from kelp to escape when threatened.