How to Distinguish from Similar Species:Chama arcana is attached by its left valve & has a waxy-translucent exterior. Its beak coils to the right (clockwise) as viewed from above.
Geographical Range: Oregon to southern Baja California. Not likely to be found north of Oregon
Depth Range: Middle intertidal
Habitat: On rocky reefs along the outer coast
Biology/Natural History: Often in large clusters on rocks along the outer coast. Often with Chama arcana and the tube snail Serpulorbis in California. Valves are thick and dense; apparently lack calcite. Related to the extinct (Mesozoic) group of rudists. The shell rotates (clockwise?) while it grows, leading to the spiral lines.
Kozloff 1987, 1996
Scott and Blake, 1998
Smith and Carlton, 1975
General Notes and Observations: Locations, abundances, unusual behaviors:
Authors and Editors of Page:
Dave Cowles (2005): Created original page