AKNOLD — Tin: I'ALEONTOLOGY AND STKATKJIUI'IIV Ol' SAN PEDKO. 219 



Gcuus Ad mete M>dkr. 



Shell oval, thin, diaphanous, covered by a thin epidermis; spire sharp; last whorl ventricosc; 

 aperture oval, feebly channeled in front, columella arcuated, obliquely truncated, with rudimentary 

 plications; outer lip sharp. 



Adniele viridula Fabr. is a cliaracteri.stic species. 



198. Admete gracilior Carpenter. 



ri,ATE VII, Fiu. 4. 



Caiicillaria gracilior Ci'R., Pal. Cal., Vol. II, p. 50, 1869. Cooper, 7th Ann. Rept. Cal. St. Min., 

 iSSS, p. 23. 



Shell small, ovate, thin; spire elevated, subacute; whorls six, rounded to subangular, crossed 

 1)V numerous prominent, rounded ridges which reach their ma.ximum jirominence on the angle of the 

 whorl; these ridges become nearly obsolete on the anterior part of the body-whorl; spiral sculpture 

 consists of numerous fine ridges and furrows; suture deeply depressed, giving shouldered appear- 

 ance to whorls; aperture ovate; outer lip thin, smooth; inner \\\) only slightly incrusted; columella 

 obliquely truncated, and having two plications on inner side; slight umbilical slit; no canal. 



Dimensions. — Long. 11 mm.; lat. 6.3 nini.; body-whorl 7.5 mm.; aperture 5.5 mm.; defl. 

 50 degrees. 



A tiiiique form, looking something liice a small Fusns robiisiits with the canal 

 gone. It is (jnite a variable species, one specimen showing a narrower spire and 

 tower, but more prominent ribs than the type, while still another showed more 

 rounded whorls and less prominent ridges. 



Fouml in the lower San Pedro series at Deadraan Island. Also obtained from 

 the Pleistocene at the bath-house, Santa Barbara; and at Port Los Angeles, near 

 Santa Monica. The specimen figured is from the lower San Pedro series at Dead- 

 man Island, and is now in the United States National Museum. 



Pleistocene. — San Pedro (Oldroyd; Arnold): Santa Barbara (Carpenter; 

 Arnold): Santa Monica (Arnold). 



Family LIV. OLIVID.E. 



Genus Olivella Sivainson. 



Shell small, polished; spire produced, acute; suture canaliculated; aperture narrow behind; 

 enlarged anteriorly; columella plicated in front, callous posteriorly. 



Olivella undatella is a characteristic species. 



199. Olivella biplicata Sowerby. 



Olivella biplicata Sby., Tank. Cat., App., p. 33, 1825. Cpr., Brit. Assn. Rept., 1863, p. 661. 

 H. & A. Adams, Gen. Rec. Moll., p. 146. Gabb, Pal. Cal., Vol. II, p. 75, 1869. 

 Trvon, Man. Conch., Vol. V, p. 87, Fl. XXXIV, fig. 58, 1883. Cooper, 7th Ann. 

 Rept. Cal. St. Min., 1888, p. 255. Keep, West Coast Shells, p. 40, fig. 20, 1892. 

 Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 212 (and varieties). 



