26Q CALIFORNIA ACADEMY OF SCIENCES. 



Pleistocene.— San Diego (Cooper): 8aii 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 ano??ia/a Stearns, Proc. Phil. Acad. Nat. Sci., 1875, p. 464, PI. 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. 



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



This large, nearly smooth species has so far been reported only from the 

 Pliocene of San Diego, where it is quite common. 



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



279. Opalia borealis Gould. 



Sea/aria dorea/is Gld., Wilkes' Exped., Vol. XII, 1852, p. 207. Tryon, Man. Conch., Vol. IX, 



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

 Opalia iorea/is Gld., Cpr., Brit. Assn. Rept., 1863, p. 660. Cooper, 7th Ann. Rept. Cal. St. 



Min., 1 888, 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 ape.x; 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. — Kamtschatka; Straits of Fuca to San Diego (Cooi)er). 



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



