CLASS PELECYPODA 
43 
divaricately grooved; inner basal margin crenulated; anterior teeth 10-14, 
posterior 9-12; valves moderately convex. Length, 23; height, 22; diam¬ 
eter, 14 mm. (Dali.) 
Type in U. S. N. M., No. 120775. Type locality, Station San Miguel 
Island, California. 
Range. Cape Blanco, Oregon, to Magdalena Bay, Lower California. 
Genus LIMOPSIS Sassi, 1827. 
Shell orbicular, convex, slightly oblique; ligamental area with a tri¬ 
angular cartilage-pit in the center; hinge with 2 equal, curved series of 
transverse teeth. (Tryon. S. S. Conch.) 
Distribution. Red Sea, Japan, Britain, Finland and United States. 
Limopsis skenea Dali, 1916. 
Proc. U. S. N. M., 52:402. 
Shell small, finely reticulately sculptured, with a long-haired velvety 
periostracum; narrow, high, rather inflated, thin, whitish under the brown 
periostracum; beaks small, area small, hinge line short, with one outer 
large and one or two small inner teeth on each side of the resilifer. General 
form oblique. Length, 7; height, 9.2; diameter, 6.5 mm. (Dali.) 
Type in U. S. N. M., No. 205883. Type locality, Station 4471, 
Bowers Bank, Bering Sea, in 30 fathoms. 
Range. Known only from the type locality. 
Limopsis akutanica Dali, 1916. 
Proc. U. S. N. M., 52:403. 
Shell white, with a golden brown long-haired periostracum, the sur¬ 
face concentrically somewhat irregularly sculptured, the ridges crossed by 
finer, closer, less conspicuous striae; disk ovate, compressed, with incon¬ 
spicuous beaks, a very small narrow area and a relatively large resilifer; 
the inner margins are flat; the hinge plate narrow, with about 7 posterior 
and 9 anterior teeth; interior of disk finely radiately striate. Length, 21; 
height, 18; diameter, 8 mm. (Dali.) 
Type in U. S. N. M., No. 224263. Type locality, Station 2842, south¬ 
east of Akutan Island, Aleutians, in 72 fathoms. 
Range. Known only from the type locality. 
Limopsis diegensis Dali, 1908. 
Plate 29, figs. 6, 7. 
Bull. Mus. Comp. Zool. , 43:395; plate 15, figs. 13, 15. 
This small, oblique-ovate, and rather swollen species is light brown, 
rather sparsely pilose, thin, with a small resilium, about seven anterior and 
