Family: Muricidae, Murexes view all from this family

Description 1/2-1 3/4" (1.3-4.4 cm) high. Oval, with elevated spire about half shell length; grayish or yellowish-white, often with brown spiral bands. Whorls convex, with about 12 low, rounded axial ribs crossed by numerous spiral cords; finer scaly spiral threads between ribs. Aperture elongately ovate, white, yellowish or brownish within. Outer lip sometimes thickened within, with 2-6 small teeth inside. Canal open, fairly broad.

Habitat On and among rubble near oyster beds, intertidally to water 25' (76 m) deep.

Range On both coasts: Nova Scotia to ne. Florida, and Washington to c. California.

Discussion This species was introduced at the same time as oysters into both California and England about 100 years ago. It is probably the greatest predator of the common Eastern Oyster, although it also feeds on other bivalves, some gastropods, and even crabs. Using its radula, it drills a hole in the prey's shell, then inserts its proboscis to feed. The eggs are laid in rounded, vaselike capsules attached by a narrow stem to a solid object. Spawning takes place all summer, and the larvae emerge as crawling young in 6-8 weeks. The closely related Gulf Oyster Drill (U. perrugatus), same size, is found on both coasts of Florida; it has fewer and larger axial ribs, which are angled at the shoulder.