Contracted Cowry Helmet Shell, Cypraecassis coarctata

Contracted Cowry Helmet Shell, Cypraecassis coarctata, Juvenile. Shell courtesy of the commercial fishermen of the greater Los Cabos area, February 2012. Size: 2.6 cm (1.0 inch) x 1.4 cm (0.6 inches).

Contracted Cowry Helmet, Cypraecassis coarctata, Transitioning Juvenile. Shell courtesy of the commercial fishermen of the greater Los Cabos area, February 2012. Size: 3.8 cm (1.5 inches) x 2.4 cm (0.9 inches).

Contracted Cowry Helmet, Cypraecassis coarctata, Adult. Shell courtesy of the commercial fishermen of the greater Los Cabos area, March 2013. Size: 7.6 cm (3.0 inches) x 4.3 cm (1.7 inches).

The Contracted Cowry Helmet, Cypraecassis coarctata (G.B. Sowerby, 1825), is a gastropod mollusk that is a member of the Cassidae Family of Helmets. They are also known as the Narrow-mouthed Helmet and in Mexico as yelmo boca ancha. The shell is cylindrical to egg-shaped with a low pointed spire. The exterior of the shell is sculpted with four rows of tubercles running the length of the body whorl and there are also finer lines spiraling down the whorl, between the tubercles. The aperture is wider at the anterior end, contracting toward the spire and the siphon canal is sharply bent. The exterior of the shell is cream to beige in color, with dark brown to reddish-brown mottling; the aperture is yellowish to orange. The Contracted Cowry Helmet Shells reach a maximum of 8.9 cm (3.5 inches) in length and 5.0 cm (2.0 inches) in height.

Contracted Cowry Helmets are found on and within sand substrate in the intertidal zone to depths up to 30 m (100 feet). They are found throughout the Sea of Cortez, and south to Peru; they have not been documented from coastal waters along the west coast of Baja.

A synonym is Cassis coarctata.