"Shell translucent yellowish white, very thin, resembling mica in consistency, oblique, compressed; beaks small, low, polished, hardly projecting beyond the hinge line; ears small, subequal, the posterior feebly differentiated; the anterior right ear with a wide fasciole corresponding to the byssal sulcus, above which are five or more radial threads, the whole with strong incremental lines; on the lower margin of the fasciole is a line of minute beads, apparently a ctenolium which becomes obsolete at maturity; the other ears are sculptured like the rest of the disk; sculpture: on the left valve a feeble but distinct 'Camptonectes’ striation, rather coarse and irregular incremental lines, the whole crossed by 40-65 fine radial, sparsely, minutely scaly threads, the scales occurring usually at the intersection with a prominent incremental line; left valve with similar sculpture except that the 'Camptonectes’ striation is so fine as to require strong magnification and a good light to be seen at all; the valves are produced obliquely downward and backward; the surface sculpture yields readily to friction and many of the valves have lost it altogether, retaining only the concentric sculpture; left valve slightly more convex; interior glassy, the resiliary pit very small, the margins entire. Height, 18; length, 18; max. diam. 2.5; hinge line, 9.5 mm. A very large specimen is 22 mm high." {fide Dall, 1908) Size: Normal adult size range is 12 to 18 mm.

From Cape San Lucas, Baja California, Mexico to Panama.
Habitat: Littoral zone to deep water, on muddy bottoms.