416 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



a prominent angle separates the posterior dorsal area from the rest of 

 the disk; surface concentrically evenly threaded, the threads a little 

 more pronounced on the doreal area; an obscure almost microscopic 

 radial striation is sometimes apparent; the siphons protrude beyond 

 the rostrum with a dense covering of wrinkled periostracum ; interior 

 white, hinge normal, the basal margin of the right valve partly over- 

 lapping that of the left valve; pallial sinus obsolete. Length, 8.5; 

 height, 4; diameter 4.5 mm., but the shell is often larger. Cat. No. 

 97039, U.S.N.M. 



Station 2838, off Lower California, in 44 fathoms, mud. The spe- 

 cies extends northward to the Santa Barbara Islands, Cahfornia. 



CORBULA KELSEYI, new species. 



Shell rather large, rounded triangular, whitish, heavy, not inflated; 

 the surface sculptured by low concentric lamellae, a little more promi- 

 nent near the posterior end of the shell, separated by equal or slightly 

 wider interspaces crossed by fine radial threads which do not crenu- 

 late the lamellae; there is no defined posterior dorsal area or keel; 

 interior with a deep anteriorly rounded pallial sinus, fused with the 

 palUal line below for the greater part of its length. There seems to 

 be a small narrow lunular area in the left valve. Length, 16; height, 

 10; diameter of left valve, 3 mm. Cat. No. 120691, U.S.N.M. 



Catalina Island, California. 



Named in honor of Prof. F. W. Kelsey of San Diego. 



PANOMYA ARCTICA Lamarck, new variety, TURGmA. 



Shell very similar to the North Atlantic form but very much more 

 capacious and larger. Length, 90; height, 60; diameter, 48 mm. 

 Cat. No. 151224, U.S.N.M. 



This form is common to the Aleutian Islands, and eastward as far 

 as the Shumagms. The type-specimen is from Popoff Strait in the 

 Shumagin group, Alaska. 



PANOMYA BERINGIANA, new species. 



Shell resembling P. arctica Lamarck, in a general way, but thinner, 

 less cylmdrical, much larger, and proportionately shorter. Length, 

 130; height, 80; diameter, 50 mm. A single valve reaches a length 

 of 150 and a height of 110 mm. Type-soecimen, Cat. No. 212875. 

 U.S.N.M. 



Station 3529, near the Pribiloff Islands, in 56 fathoms. Eastern 

 Bering Sea in general, 



SAXICAVELLA PACIFICA, new species. 



Shell small, thin, white, with a pale olive dehiscent periostracum ; 

 inequilateral, the anterior end shorter and more attenuated, the pos- 

 terior longer, more vertically expanded; surface sculptured only by 



