266 CALIFORNIA ACADEMY OF SCIENCES. 



Pleistocene. — San Diego (Cooper): 8an Pedro (Cooper; Arnold): Ventura; 

 San Diego (Arnold). 



Pliocene. — San Diego (Cooper; Arnold). 



Genus Opalia H. & A. Adams. 



Shell turriculated, imperforate; whorls united, the last with a rib at the base. 

 Opalia coronata Lam. is a characteristic species. 



[S. D.] Opalia anomala Stearns. 



Opah'a anofna/a Stearns, Proc. Phil. Acad. Nat. Sci., 1875, p. 464, PL XXVII, fig. i. Cooper, 

 7th Ann. Rept. Cal. St. Min., 1888, p. 255. Dall, Trans. Wagner Inst. Sci., Vol. Ill, 

 Part 2, 1892, p. 245. 



Shell solid, imperforate, elongated, conical; spire gradually tapering; whorls convex, when 

 perfect probably eleven to fourteen in number, nearly smooth, being marked only by incremental, 

 and, in some specimens, by an outgrowth varix; suture well defined; basal whorl traversed spirally 

 by an inconspicuous rib, varying in prominence, in some specimens barely discernible; the convexity 

 or angularity of the lower part of the basal whorl modified by the presence or absence of the 

 basal rib. 



Dimensio7is. — Long. 53 mm.; lat. 19 mm.; body-whorl 24.5 mm.; aperture 11 mm. 



This large, nearly smooth species has so far been re^wrted only from the 

 Pliocene of San Diego, where it is quite common. 



Pliocene. — San Diego (Hemphill; Stearns; Arnold). 



279. Opalia borealis Goidd. 



.Sba/arza i5i?rifa/w Gld., Wilkes' Exped., Vol. XII, 1S52, p. 207. Tryon, Man. Conch., Vol. IX, 



p. 76, PI. XVI, fig. 89, 1887. 

 Opalia borealis Gi.T>., Cpr., Brit. Assn. Rept., 1863, p. 660. Cooper, 7th Ann. Rept. Cal. St. 



Min., 18S8, p. 255. Keep, West Coast Shells, p. 49, fig. 30, 1892. 

 Scala (Opalia) borealis CpR., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 210. 



Shell small, turreted, thick; apex generally decollated; whorls seven, only slightly convex; 

 varices eight, rounded, thick, prominent, and forming radiating ridges from the apex; suture im- 

 pressed, distinct; body-whorl squarely angulated at base, with keel on angle; base flat, smooth; 

 aperture subovate; outer lip thin, effuse; inner lip only slightly incrusted. 



Dimensions. — Long. 15 mm.; lat, 6 mm.; defl. 22 degrees. 



The specimens described were identified by Dr. Dall. 



Rare in upper San Pedro series of San Pedro; two specimens. 



Living. — Karatschntka; Straits of Fuca to San Diego (Cooper). 



Pleistocene. — Santa Barbara (Cooper): San Pedro (Arnold). 



