ARNOLD— THE PALEONTOLOGY AND STIUTIGRAPHY OF SAN PEDRO. 291 



The specimen figured was obtained from the lower San Pedro series at San 

 Pedro, and is now in the private collection of Delos Arnold. 



Living. — Monterey to Panama (Cooper): Catalina Island, 20 fathoms 

 (Arnold, 1901). 



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



Family LXIX. CERITHllDiE. 



Genus Bittium Leach. 



Shell elevated, with numerous granular whorls and irregular varices; anterior canal short, 

 not recurved; inner lip simple; outer lip not reflected, usually with an exterior rib. 



Bittium reticulatum Da Costa is a characteristic species. 



315. Bittium asperum Gabb. 



Turbonilla aspera Gabb, Proc. Phil. Acad. Nat. Sci., 1861, p. 368. 



Bittium asperum Gabb, Cpr., Ann. & Mag. Nat. Hist., 3rd Sen, Vol. XVII, 1866, p. 276. Gabb, 

 Pal. Cal., Vol. II, p. 72, PI. II, fig. 20, 1869. Tryon, Man. Conch., Vol. IX, p. 153, 

 PI. XXX, fig. 7, (887. Cooper, 7th Ann. Kept. Cal. St. Min., 18S8, p. 230. 



Bittium asperum Cpr., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 205. 



Shell small, slender, turreted; ape.x elevated, acute; whorls nine to ten, nearly flat on 

 posterior portion, with prominent angulation anteriorly; sculpture consists of three spiral ridges, 

 crossed by sixteen to eighteen much more prominent ridges; suture deep, distinct; aperture semi- 

 elliptical, with prominent basal emargination instead of a canal; lip thin, inner side crenulated; body- 

 whorl angulated, base slightly sculptured spirally. 



Dimetisions. — Long. 10.5 mm.; lat. 31 mm.; aperture 2.5 mm. x 1.5 mm.; defl. 22 degrees. 



This species may be distinguished by the relative prominence of its trans- 

 verse sculpture. Specimens identified by Dr. Dall 



Common in the Pliocene at Deadman Island and Timm's Point; rare in the 

 lower San Pedro series of Deadman Island, and found only occasionally in the upper 

 San Pedro series of Crawfish George's and San Pedro. Found in the Pleistocene at 

 bath-house, Santa Barbara; at Barlow's ranch, Ventura; and at Pacific Beach, 

 San Diego. 



Living. — Santa Barbara to Catalina Island (Cooper). 



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

 Santa Barbara; San Diego (Arnold). 



Pliocene. — San Diego well (Dall): San Pedro (Arnold). 

 316. Bittium californicum Dall & Bartsch. 



Pl.\te IV, Fig. 4. 



Bittium {E/ac/iista) californicum. Dall & Bartsch, Nautilus, Sept., 1901, p. 58. 



Shell, small, thin, white, turreted; spire elevated, mammilliform ape.x; whorls eight, convex, 

 slightly more angular on anterior portion of whorl; whorls crossed by twelve or thirteen prominent. 



