302 CALIFORNIA ACADEMY OF SCIENCES. 



lower San Pedro series of Deadraan Island; found also in the lower San Pedro 

 series at San Pedro; and in the Pliocene of Deadman Island. 



Living. — Sitka; San Diego (Cooper). 



Pleistocene. — San Nicolas Island; San Diego (Cooper): San Pedro (Arnold). 



333. Littorina scutulata Gould. 



Littorina scutulata Gld., Proc. Bost. Soc. Nat. Hist., Vol. Ill, 1849, p. 83; Wilkes' Expl. Exped., 



Vol. XII, p. 200, fig. 241, 1852. Cpr., Brit. Assn. Rept., 1863, p. 656. Tryon, Man. 



Conch., Vol. IX, p. 250, PI. XLV, figs. 98-103, 1887. Cooper, 7th Ann. Rept. Cal. 



St. Min., 1888, p. 246. Keep, West Coast Shells, p. 68, fig. 52, 1892. Williamson, 



Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 205. 

 Littori7ia plena Gld., Proc. Bost. Soc. Nat. Hist., Vol. Ill, 1849, p. 84; Wilkes' Expl. Exped., 



Vol. XII, p. 201, fig. 236, 1852. 



Shell small, conical; spire elevated, subacute; whorls four, very slightly convex, the last one 

 ventricose and slightly angulated; sculpture consists of numerous nearly obsolete, spiral striae, and 

 fine, oblique, incremental lines; aperture ovate; outer lip thin, lower part effuse; inner lip incrusted, 

 effuse; color reddish brown. 



Dimensioyis. — Alt. 10 mm.; lat. 6 mm.; aperture 5 mm. x 3 mm.; defl. 48 degrees. 



All the specimens from the Pleistocene that have been examined show a 

 characteristic reddish brown color. Several specimens identified by Dr. Dall; among 

 them two which were marked "variety," but which have been included in this species 

 for lack of constant varietal differences. 



Found in the lower San Pedro series at Deadman Island and San Pedro; and 

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

 Beach, and Deadman Island. Found in the Pleistocene at Barlow's ranch, Ventura; 

 and at Pacific Beach and Spanish Bight, San Diego. 



Living. — Monterey to San Diego (Cooper). 



Pleistocene. — San Pedro to San Diego (Cooper): San Pedro; Ventura; San 

 Diego (Arnold). 



Genus Lacuna Turton. 



Shell turbinated, thin; aperture semilunar; columella flattened, with an umbilical fissure. 



Lacuna pallidula Da Costa is a characteristic species. 



334. Lacuna compacta Carpenter. 



Lacuna ? var. compacta Cpr., Brit. Assn. Rept., 1863, p. 656. 



Lacuna {? solidula, var.) compacta Cpr., Ann. & Mag. Nat. Hist., 3rdSer., Vol. XIV, 1864, p. 429. 

 Tryon, Man. Conch., Vol. IX, p. 266, PI. L, fig. 71, 1887. 



Shell small, thin, compact; spire elevated, subacute; whorls four, slightly convex; body- 

 whorl prominently angulated at base; suture impressed, distinct; aperture ovate; outer lip not effuse^ 

 thin; inner lip slightly effuse; chink very small, almost obsolete; surface faintly marked with very 

 fine incremental lines. 



Dimensions. — Long. 6 mm.; lat. 4 mm.; aperture 3 mm, x 2 mm.; defl. 60 degrees. 



