CLASS PELECYPODA 
201 
Sphenia truncula Dali, 1916. 
Proc. U. S. N. M., 52:415. 
Shell short, whitish with a dirty ash-colored periostracum, rude and 
more or less distorted, abruptly truncate, almost equilateral, the anterior 
portion swollen, the posterior part attenuated. Length, 7 ; height, 4.3; 
diameter, 4 mm. (Dali.) 
Type in U. S. N. M., No. 160116. Type locality, San Diego, California. 
Range. San Diego, California, to Panama. 
Sphenia pholadidea Dali, 1916. 
Proc. U. S. N. M. } 52:415. 
Shell small, thin, white, with a blackish periostracum, which is con¬ 
spicuously laminate on the posterior dorsal area; very inequilateral, the 
anterior side shorter, the beaks inconspicuous, 4 mm. behind the anterior 
end; sculpture of rude incremental lines, posterior end abruptly truncate, 
hardly attenuated; pallial sinus rounded, not reaching the vertical of the 
beaks; hinge with a prominent tooth-like projection in the right valve 
behind the resilifer. Length, 12; height, 5.3; diameter, 4 mm. (Dali.) 
Type in U. S. N. M., No. 2581. Type locality, Santa Barbara, Cali¬ 
fornia. 
Range. Known only from the type locality. 
Sphenia globula Dali, 1919. 
Proc . U. S. N. M. t 56:370. 
Shell small, white, with a dehiscent, brownish, papery periostracum 
which extends beyond the shell at the siphonal end; almost spherically 
inflated, short, truncate behind; beaks inconspicuous, situated about the 
middle of the valves; anteriorly the valves are rounded; behind they are 
compressed into a short rostrum about one-fourth the whole length; 
sculpture of rather rude lines of growth, the external layer obscurely 
granulose, especially in front; interior of the valves chalky white, the 
muscular impressions distinct, the pallial sinus rounded, slightly less than 
half the length of the valve, its impression formed by two almost separate, 
rather broad, patches; hinge as usual in the genus. Length, 12; height, 9; 
diameter, 9 mm. (Dali.) 
Type in the Oldroyd Coll., Stanford University, No. 312. Type locality, 
Monterey, California. 
Range. Known only from the type locality. 
