The Rock Venuses

Genus VENERUPIS, Lam. (RUPELLARIA, Fl. De Bellevue)

Shell bivalve, gaping, elongated; beaks well forward; posterior truncated; surface decorated with concentric, frill-like laminae. Thirty species. Mollusks live in holes in rocks, attached by byssus. They frequent temperate and cold seas.

The Frilled Rock Venus (V. lamellifera, Conr.) nestles among rocks on northern Pacific beaches. It is white with many thin, papery frills adorning the valve. Usually broader at the posterior end, and truncated, yet it takes on many forms, to adapt itself to rock crevices. Length, 1 to 2 inches.

Habitat.-California northward.

The Leafy Rock Venus (V. foliacea, Desh.) is the most beautiful shell in the genus. The wavy frills are yellowish beneath and tinged with rosy violet toward the margins. Each frill turns a corner as it crosses a ridge running from the hinge to the sharply angular junction of the ventral and posterior margins. Under the laminae faint radiating lines are seen in pairs. Length, 2 inches.

Habitat.-Mazatlan.