CLASS PELECYPODA 
137 
Genus BORNIA Philippi, 1836. 
Shell elongately oval, with slightly projecting beaks, almost equilateral, 
surface finely concentrically striated; hinge with three teeth in the left 
valve, two small anterior and one somewhat remote and elongated pos¬ 
terior, right valve with only two diverging elongated cardinal teeth; 
cartilage situated in a groove in front of the posterior teeth; muscular 
impressions faintly marked. (Tryon. S. S. Conch.) 
Type. Erycina corbuloides Bivona. 
Distribution. Norway, New Zealand and California. 
Range in time. From the Eocene to the present. 
Bornia retifer Dali, 1899. 
Proc. U. S. N. M., 21:889; pi. 87, fig. 2. 
Shell thin, white, moderately convex, rounded, trigonal, nearly equi¬ 
lateral; beaks distinct, not high; surface polished, with faint incremental 
lines and minute close punctations whose interspaces give the effect of a 
fine netting; hinge normal, delicate; adductor scars rounded, high up; 
posterior basal margin very slightly crenulated. Length, 12; height, 9; 
diameter, 4 mm. (Dali.) 
Type in U. S. N. M. Type locality, Station 2900, off Santa Rosa 
Island, California, in 13 fathoms. 
Range. Monterey to Santa Barbara, California. 
Genus LEPTON Turton, 1822. 
Shell suborbicular, compressed, smooth or shagreened, a little opened 
at the ends and longest behind; hinge teeth 0.1 or 1.1 in front of an angular 
cartilage notch; lateral teeth, 2.2 and 1.1. (Tryon. S. S. Conch.) 
Type. Solen squamosns Montagu. 
Distribution. Universal. Laminarian and coralline zones. 
Range in time. Eocene. 
Lepton meroeum Carpenter, 1864. 
Suppl. Rep. Brit. Assoc., p. 643. 
Shell shaped like Sunapta. (Carpenter.) 
Type locality, between San Pedro and San Diego, California. 
Range. San Pedro to San Diego, California. 
Genus LASZEA Leach, 1827. 
Shell minute and roundish oval; beaks straight; cartilage long, placed 
at the shorter end of the shell, contrary to that in Kellia ; left valve with 
a minute thorn-like cardinal tooth; and in each valve two remarkably 
strong teeth. (Tryon. S. S. Conch.) 
