MARINE MOLLUSKS — MACGINITIE 169 



from 1 to 2 years old; one 10.8 mm., about 2 years; one 16.5 mm., 

 about 4 years; and one 20.6 mm., about 5 years old. There is some 

 evidence indicating that if a large series were available from one 

 localitAT-, they could easily be sorted into age groups on the basis of size. 



In the specimens taken at 453 feet on Oct. 11, 1949, the females 

 greatly outnumbered the males. The females contained eggs that 

 were not quite mature, measuring about 292/i, including the membrane. 

 Of 9 specimens taken through the ice at 162 feet on Feb. 18, 1950, 

 3 were so immature that tiie sex could not be determined without 

 making sections, 4 Vv'ere males with fairly well developed testes, 1 had 

 immature eggs, and 1 had some fairly well developed eggs. Six of 

 the eggs from the latter specimen measured 324, 316, 291.5, 283.4, 

 283.4, and 234. 9/^, an average of 2SS/i; the yolk portion measuring 

 from 105.3 to 218. 7^, and averaging 162ju. 



This species forms a favorite food of Natica and Polinices and 

 drilled shells are common in dredge hauls. 



Distribution: A. montagui occurs in all Arctic seas; in the Pacific 

 as far south as British Columbia; in the western Atlantic as far south 

 as Massachusetts, and in the eastern iltlantic as far south as the Bay 

 of Biscay. Point Barrov,^ is a new locality. This is a nevv^ name in 

 our list of Pacific mollusks. 



Family Carditidae 



Genus Cardita Lamarck, 1799 



Cardita crebricostata (Krause, 1885) 



Cardita borealis var. crebricostata Krause, 1885a, p. 30, pi. 3, fig. 4. 

 Venericardia alaskana Dall, 1903b, pp. 710, 715; 1903a, pi. 63, fig. 7. 

 Venericardia crebricostata 01dro3'd, 1924, p. 114, pi. 13, fig. 12. 



Two worn right valves, measuring 27.2 mm. long by 24.5 mm. 

 high, and 29.6 by 25.9 mm., were taken at 140 feet on Aug.21,1949, 

 and a somewhat broken valve was washed ashore. 



Other material examined: All the specimens in the U. S. 

 National Museum labeled V. alaskana and V. crebricostata. 



Discussion: With the exception of 3 specimens from the vicinity of 

 Monterey, all of the specimens labeled C. alaskana are C. crebricostata. 

 Specimens from Puget Sound and the coast of Oregon conform to the 

 specifications for C. crebricostata, but those from Monterey are 

 probably C. ventricosa. 



Distribution: Point Barrow south and east to the Aleutians, 

 British Columbia, Puget Sound, and the coast of Oregon. 



