170 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



than the posterior; base very broadly rounded; hinge plate 

 fairly broad ; chondophore oblique, shallow, apically roofed by 

 a broad flat spur; left cardinal prominent, high, arms broad, ex- 

 tending from the dorsal to the ventral margin of the plate; 

 ventral sinus, narrow, deep; right cardinal with a prominent 

 anterior arm and with a well developed, but very thin, posterior 

 arm; laminae long, fairly distant from beaks; anterior lateral 

 formed from the margin of the plate, top acute; posterior 

 lateral also with acute top, dorsal and ventral slopes nearly 

 equal; anterior ventral lamina formed from upturned edge of 

 the hinge plate not confluent with the anterior dorsal cardinal 

 arm. 



Dimensions: — Length, 53 mm. ; height, 39 mm. ; convexity, 

 11 mm. 



This species has the same general outline as vS". merriami 

 Packard, but its sculpturing on the anterior dorsal area is differ- 

 ent, its posterior less sharply truncated and the laminae more 

 divergent. 



Type: — No. 395, Cal. Acad. Sci. Locality 181, near Vader, 

 Lewis County, Washington, on east bank of the Cowlitz River, 

 just back of the Greeco ranch house, about four miles east of 

 Vader. 



Named for Professor Earl L. Packard of the University of 

 Oregon, whose excellent work on West Coast Mactrinae has 

 made the members of this subfamily very useful to workers in 

 paleontology. 



Semele reagani, new species 

 PI. 29, Figs, la, lb, Ic and Id 



Shell medium size with prominent subcentral beak; lunule 

 and escutcheon obscure; anterior dorsal margin slightly con- 

 cave ; posterior dorsal margin straight, sloping to rounded pos- 

 terior ; anterior sub-truncate ; a faint umbonal ridge cutting fine 

 rounded, growth lines decorating shell. 



Dimensions: — Length, 13.5 mm.; height, 12.5 mm.; con- 

 vexity, 2.5 mm. 



Type:—^o. 396, cotype 397, Cal. Acad. Sci. Locality 181, 

 near Vader, Lewis County, Washington, on east bank of the 



