118 CALIFORNIA ACADEMY OP SCIENCES. 



and San Pedro. Found also in tlie Pleistocene at Barlow's ranch, Ventura, and in 

 tlie Pleistocene of Spanish Bight and Pacific Beach, San Diego. 



Living. — Monterey to Mexico (Cooper). 



Pleistocene. — San Pedro (.Cooper; Ai'nold): Ventura; San Diego (Arnold). 



[S. D.] Anomia limatula Dull. 



Anomia limahda Dall, Proc. U. S. Nat. Mu.s., Vol. I, 1879, p. 15. Trans. Wagner Inst. Sci., Vol. 

 Ill, Part 4, 1898, p. 785, PI. XXXV, fig. 19. 



Shell large, thin, irregular, with a rather thickened hinge-line; external surface rough, like 

 fiesh fractured china-ware ; surface devoid of all normal radial sculpture, and still retaining on its 

 yellowish valves traces of dark purple, irregularly radial blotches. The calcareous plug of this 

 species is peculiar, being hollow, and the cylinder incomplete on one side. 



Distinguishahle from A. lampe and Pododesmiis macroschisma b}' its lack of 

 radial sculpture. Reported in the Pleistocene of San Pedro by Stearns. 



Pleistocene. — San Pedro (Stearns): Ventura County, eight miles inland and 

 two hundred feet elevation above sea-level (Bowers): Si)anish Bight and Coronado 

 Beach, San Diego (Hemphill; Stearns): Twenty-sixth Street, San Diego (Hemphill; 

 Arnold). 



Superfamily MYTILACEA. 



Family XII. MYTILID.T:. 



Genus Mytilus (Linnf) Bolten. 



Shell wedge-shaped, rounded behind; umbones terminal, pointed ; hinge-teeth minute or 

 obsolete; pedal muscular impressions two in each valve, small, simple, close to the adductors. 



Mytilus smaragdinns Chemn. is a characteristic species. 



Section Mytilus .s. .s. 

 Surface with chiefly concentric sculpture, or smooth. 

 Type, Mytilus eduHs Linnc. 



40. Mytilus edulis Linne. 



Mytilus edulis Linn., Syst. Nat., Ed. X, 1758, p. 705. = M. Lwrcalis Lam. = M. abbrcviatus Lam. 



= M. velustus Lam. = /J/, incurvatus Lam. = M. pcllucidiis Pennant = M. notatus 



DEK;yY = M. subsaxatilis Williamson [fide Carpenter. Brit. Assn. Rept. , 1856, p. 



219). Carpenter, Brit. Assn. Rept., 1863, p. 643. Cooper, 7th Ann. Rept. Cal. St. 



Min., 1888, p. 252. Keep, West Coast Shells, p. 173, 1892. Williamson, Proc. 



U. S. Nat. Mus., Vol.XV, 1892, p. 191. = Modiola piilcx H. C. Lea (not of Lam.) 



= Mytilus minganensis Mighels, &c. {fide Dall, Wagner Inst. Sci., Vol. Ill, Part 4, 



1898, p. 788). 

 Mytilus pedrmviis Con., Pac. R. R. Rept., Vol. V, 1853, p. 325, PI. V, fig. 40. 



