ARNOLD— THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 261 



270. Purpura crispata Chemnitz. 



Purfnira crispata Ciiem., Conch. Cab., XI, PI. 187, figs. 1S02 and 1S03, 1795; Kustek, Conch. Cab., 

 p. 105, PI. XIX, figs. 3 and 4, 1837. Cpr., Brit. Assn. Rept., 1863, p. 662. Tryon, 

 Man. Conch., Vol, II, p. 175, PI. LXIII, figs. 163-166, 168, 1880. Cooper, 7th Ann. 

 Rept. Cal. St. Min., 1SS8, p. 261. Keep, West Coast Shells, p. 33, fig. 13, 1S92. 



Shell fusiform, thick; spire elevated; apex subacute; whorls five to seven, convex or 

 ang^lated, with one or more prominent spiral ridges on angular part of whorl; suture impressed, 

 distinct; aperture ovate to elliptical; outer lip efTiise, generally denticulate; inner lip incrusted, 

 smooth; canal short, curved backwards; umbilicus subperforate. 



Dimensions. — Long. 34 mm.; lat. 20 mm.; body- whorl 26 mm.; aperture, including canal, 

 22.5 mm.; canal 6 mm.; detl. 55 degrees. 



The specimen whose dimensions are given was a small one, but the relative 

 projiortions in this specimen seemed to be about the average. A very variable species, 

 some being nearly smooth and some almost spinous in their roughness. The smooth 

 forms generally lack the denticulation of the outer lip. The shell texture is very 

 well preserved in most of the Pleistocene specimens, some of tliera being almost 

 indistinguishable from living shells. 



Not common in the upper San Pedro series of San Pedro, Deadraan Island, 

 and Crawfish George's. Found in the Pliocene at Pacific Beach and Russ School, 

 San Diego. 



Living. — Sitka to Santa Barbara (Cooper). 



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



Pliocene. — Seven Mile Beach, San Mateo County (Cooi)er) : San Diego (Arnold). 



271. Purpura saxicola Valencienne.'i. 



Purpura saxicola Val., Venus, PI. VIII, fig. 4, 1846. Cpr., Brit. Assn. Rept., 1863, p. 662, 

 ^P. lapillus Cooper (not Linn, sp.. Lam.), Gabb, Pal. Cal., Vol. II, p. 75, 1869. 

 Tryon, Man. Conch., Vol. II, p. 174, PI. LIII, figs. 152, 154a, 1880. Cooper, 7th 

 Ann. Rept. Cal. St. Min., 1888, p. 262. Keep, West Coast Shells, p. 31, fig. 11, 1892. 



Shell small, semiglobular; spire slightly elevated; apex subacute; whorls four, angulated, 

 tabular on top; body-whorl ventricose; surface ornamented with obsolete spiral ridges and fine 

 incremental lines; suture impressed, distinct; aperture large, elliptical; outer lip smooth, thin, effuse; 

 inner lip and columella flattened, incrusted, sharp; canal short. 



Dimensions. — Long. 18 mm.; lat. 13 mm.; aperture, including canal, 16 mm.; canal 

 13.5 mm.; defl. 85 degrees. 



Quite a variable form. All the Pleistocene specimens at hand show the 

 mottled or banded reddish brown coloration. Distinguishable from P. crispata by 

 the small spire, large body-whorl, large aperture, and smoothness of the shell. 



Rare in upper San Pedro series of San Pedro; three specimens. Found in 

 the Pleistocene at irrigating ditch, Ventura. 



Living. — Alaska to San Diego; Lower California (Cooper). 



