MARINE MOLLUSKS — MACGINITIE 173 



Distribution: Point Barrow, Cape Lisburne, Aleutian Islands, and 

 Sitka Ba}^, Alaska. Point Barrow is a new locality and represents an 

 extension of range of over 2 degrees of latitude. 



Family Leptonidae 



Genus Pseiidopythina Fischer, 1878 



Pseudopythina conipressa Dall, 1899 



Plate 19, figuees 2, 3, 5 



PseudopytJmia conipressa Dall, 1899, p. 888, pi. 87, figs. 1, 8.— Oldroyd, 1924, 

 p. 136. 



A specimen measuring 11.6 mm. long by 8.5 mm. high and 3.3 mm. 

 in breadth washed ashore on Aug. 27, 1949, and a right valve 6.8 by 

 4.9 mm. washed ashore on Oct. 16, 1949. 



Other material examined: The type (from 23 fathoms from 

 southwest of Hagemeister Island) and 18 shells and 5 valves from 

 17 stations, including Cape Lisburne (3 dead shells), Norton Sound 

 (1 dead shell), Nunivak Island, the Aleutians, the Shumagins, Kodiak 

 Island, Sitka Harbor, British Columbia, La Jolla, California, and 

 off Acapulco, Mexico. With the exception of about 4 specimens, all 

 of these were dead and sometimes beach-worn shells. 



Discussion: Oldroyd's (1924) figure 11 of plate 11 is of P. rugifera 

 and not of P. com,pressa as labeled. This error, coupled with the fact 

 that Dall, in his description of P. compressa, failed to call attention to 

 the spinules on the dorsal margin of the right valve, has resulted in 

 some workers trying to separate, on the basis of minute differences, 

 specimens of P. rugifera into P. rugifera and P. compressa, when, in 

 actuality, the two species are quite distinct. One of the specimens 

 figured here (pi. 19, fig. 2) has 4 spinules on the dorsal margin posterior 

 to the beaks and one anterior to the beaks. The number of these 

 spinules is greater in large specimens than in small specimens. 



Distribution: Point Barrow south through Bering Sea and east 

 and south to British Columbia; off the Columbia River, Oregon, off 

 southern California, and off Baja California, Mexico. Point Barrow is 

 a new locality. 



Genus Mysella Angas, 1877 



Mysella sovaliki, new species 



Plate 4, figure 10 



Shell minute, white, subelliptical, tumid, sturdy for its size, covered 

 with a pale tan periostracum; posterior margin rather abrupt, anterior 

 gently sloping, ventral margin convex, anteroventral margin some- 

 what produced, evenly rounded. Beaks very low, located about 

 two-thirds the distance back from the anterior end. Sculpture of 



