168 CALIFORNIA ACADEMY OF SCIENCES. 



115. Psammobia (Psammobia) edentula Gahb. 



Silequaria edcntiila Gabb, Pal. Cal., Vol. II, p. 53, PI. XV, tig. 11, 1869. Cooper, 7th Ann. 



Rept. Cal. St. Min., 1888, p. 264. 

 Psammobia edenhi/a Gabb, Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 1900, p. 976. 



Shell large, elongated, subelliptical, flattened, thin; beaks minute, posterior to middle; 

 surface marked by distinct lines of growth most prominent near the margin; cardinal margins 

 straight, sloping gently toward the ends; anterior end convexly and very obliquely subtruncate 

 above, produced and rounded below; posterior end broadly and regularly rounded, a little less 

 prominent below than above the middle; basal margin nearly straight; ligamental area long, pro- 

 jecting prominently beyond the cardinal line for nearly half the length of the anterior portion of the 

 shell; projected area with large groove on outside, flat on inside; two prominent cardinal teeth, 

 anterior less prominent and oblique; anterior muscle-impression large, subcircular; posterior smaller, 

 subelliptical; pallial sinus deep and wide. 



Dimetisions. — Long. 135 mm.; alt. 6g mm.; diam. 13 mm. 



This fine shell was originally described by Gabb from a specimen obtained in 

 the Pliocene of San Fernando. On account of the matrix in which his specimen 

 was imbedded, the hinge area and interior were only partly accessible, hence it was 

 deemed expedient to more fully describe the interior of the shell. Dr. Dall pro- 

 nounced the shell described above a member of the genus Psammobia. The cardinal 

 teeth, however, are rather large for one of this genus. 



Rare in the upper San Pedro series of San Pedro; three good specimens 

 obtained. 



Living. — ? 



Pleistocene. — San Pedro (Arnold). 



Pliocene. — San Fernando (Cooper). 



Genus Sanguinolaria Lamarck. 

 Section Nuttallia Dall. 



Shell large, suborbicular, inequivalve, more or less twisted, the right valve slightly flatter; tiie 

 posterior cardinal in the left valve obsolete; the pallial sinus narrow in front and somewhat detached 

 from the p.illial line. 



Type, Sanguinolaria nultaUi Conrad. 



116. Sanguinolaria (Nuttallia) nuttalli Conrad. 



Sanguinolaria nuttalli Con., Jour. Pliil. Acad. Sci., Vol. VII, 1837, p. 230, PI. XVII, tig. 6. 

 Carpenter, Brit. Assn. Rept., 1863, p. 638. Keep, West Coast Shells, p. 19S, 

 fig. 170, 1892. Williamson, Proc. U. vS. Nat. Mus., Vol. XV, 1892, p. 185. Dall, 

 Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 1900, p. 979. 



Shell large, subovate, thin; right valve ventricose, left compressed; umbones small, distant 

 from anterior margin, slightly prominent, acute; surface smooth, e.xcept for fine incremental lines; 

 anterior dorsal margin sloping concavely; posterior end evenly rounded from beaks; anterior end 

 more sharply rounded and much more produced; ventral margin evenly curved; cardinal teeth 

 prominent, fragile; ligamental area prominently projecting beyond cardinal line. 



Dimensions. — Long. 80 mm.; alt. 59 mm.; diam. 23 mm. 



