172 CALIFORNIA ACADEMY OF SCIENCES. 



Pliocene. — Santa Rosa; San Ramon, Kirker's Pass, Contra Costa County; San 

 Fernando; San Diego well (Cooper). 



Miocene. — Tomales, Marin County; Martinez, Contra Costa County (Cooper). 



121. Solen sicarius Gould. 



Solen sicanus GiA). , Proc. Bost. Soc. Nat. Hist., Vol. Ill, 1850, p. 214; Wilkes' Expl. Exped., 

 Vol. XII, p. 287, fig. 501, 1852. Carpenter, Brit. Assn. Rept., 1863, p. 638. 

 Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 265. Keep, West Coast Shells, 

 p. 202, fig. 173, 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 184. 

 Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 1900, p. 952. 



Shell of medium size, elongated, transversely oblong, cylindrical, slightly falcate; beaks 

 terminal; anterior extremity truncate obliquely at angle of about 30 degrees, somewhat everted, the 

 portion posterior to a line across from the beak to the base, concave; posterior extremity rounded; 

 dorsal edge rectilinear; ventral edge regularly arcuate; surface undulated by lines of growth; hinge 

 with single, erect, recurved, triangular tooth in each valve. 



Dimetisions. — Long. 63 mm.; alt. 16 mm.; diam. 9 mm. 



Distinguishable by its terminal beak and rather falcate outline. Specimens 

 identified by Dr. Dall. 



Rather rare in the Pleistocene at Deadman Island and Timm's Point; com- 

 mon in the lower San Pedro series at Deadraan Island and San Pedro; rare in 

 the upper San Pedro series at Los Cerritos, San Pedro, Crawfish George's, and 

 Deadman Island. 



Living. — Straits of Fuca to San Pedro; Japan (Cooper). 



Pleistocene. — San Pedro (Arnold). 



Pliocene.— Twelve Mile Creek, San Mateo County; San Fernando (Cooper). 



Miocene. — Walnut Creek, Contra Costa County (Cooper). 



Genus Siliqua Megerle. 



Shell smooth, oblong; epidermis polished; an umbonal rib extending across the interior of 

 the valve; pallial sinus short. 



Type, Solen radius Linne. 



122. Siliqua lucida Conrad. 



Soleairtus lucida CoN., Jour. Phil. Acad. Sci., Vol. VII, 1837, p. 232, PI. XVII, fig. 9; =6". radiata 

 Linn. {,fide Conrad, Jour. Phil. Acad. Sci., 1849, p. 214). Dall, Solenidee, Proc- 

 U. S. Nat. Mus., Vol. XXII, 1900, p. 109. 



Siliqua lucida CoN., Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 1900, p. 957. 



Shell of medium size, oblong-oval, compressed, thin, fragile; umbo a little less than one- 

 fourth length from posterior end; interior raised callus sharp, narrow, perpendicular to dorsal margin; 

 other characteristics the same as in var. nuttalli. 



Dimensions. — Long. 32 mm.; alt. 12 mm.; diam. 5 mm.; umbo to anterior end 25 mm. ; to 

 posterior end 7 mm. 



