ARNOLD — THE PALEONTOLOGY AND STUATIGRAPHY OF SAN PEDRO. 317 



Family LXXIX. LAMELLARIID.E. 



Genus Lamellaria Montagu. 



Shell ear-shaped; thin, pellucid, fragile; spire very small; aperture large, patulous; inner 

 lip receding. 



Lamellaria perspicua is a characteristic species. 



357. Lamellaria stearnsii Dull. 



Lamellaria stearnsii Dall, Am. Jour. Conch., Vol. VII, 1872, p. 122, PI. XV, fig. 6. Tryon, 

 Man. Conch., Vol. VIII, p. 63, PI. XXVII, figs. 12 and 13, 1886. Keep, West Coast 

 Shells, p. 47, fig. 27, 1892. Dall, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 211. 



Lamellaria depressa Dall, mss., 1866 {^fide Dall). 



Shell suborbicular, depressed; spire hardly elevated above last whorl; whorls three, convex; 

 columella sharp, thin, widely arcuate, loosely twisted, so that the apex is discernible from below; 

 suture distinct; aperture very effuse, rounded; marked by lines of growth, crossed by microscopic 

 fine revolving striae. 



Dimensions. — Long. 15.2 mm.; lat. 11 mm.; alt. 7 mm. 



Somewhat resembles Sigaretus debilis, but smaller, smoother, and more inflated. 

 Rare in lower San Pedro series of Deadman Island; one specimen. Found 

 also in the Pleistocene at Twenty-sixth Street, San Diego. 



Living. — Monterey (Dall) : San Pedro (Williamson) : West Coast (Keep). 

 Pleistocene. — San Pedro; San Diego (Arnold). 



Superfamily DOCOGLOSSA, 



Family LXXX. ACM^IDiE. 



Genus Acmaea EschschoUz. 

 Shell solid, patuliform; apex erect or anteriorly inclined. 

 Acmcea mitra Esch. is a characteristic species. 



358. Acmaea depicta Hinds. 



Patelloida depicta Hds., Ann. Nat. Hist., Vol. X, 1842, p. 82; Voyage Sulphur, p. 53, No. 217, 1844. 

 Nacella depicta Hds., Proc. Zool. See, 1856, p. 204. Cpr., Brit. Assn. Rept., 1863, p. 650. Keep, 

 West Coast Shells, p. 103, 1892. 



Shell small, conical, with elongate-elliptical base; apex inconspicuous, about one-fifth length 

 from posterior extremity; surface ornamented by radiating narrow bands of color. 

 Dimensions. — Long. 7 mm.; lat. 2.8 mm.; alt. 1.8 mm. 



This species is close to A. paleacea, but is slightly broader, more depressed, 

 and has bands of brown radiating from the apex. 



One specimen from the upper San Pedro series at Crawfish George's. 

 Living. — San Diego (Carpenter). 

 . Pleistocene. — San Pedro (Arnold). 



