ARNOLD — THE PALEONTOLOGY AND STRATIQllAPHY OF SAN PEDRO. 245 



241. Murex (Pterorhytis) foliatus Mart;in. 



Cerosioma folialiim Martyn, Univ. Conch., No. 66, PI. XXIV, fig. i, 1784. Cpk., Biit. Assn. 



Kept., 1863, p. 663. Keep, Common Sea Shdls, PI. XIV, fig. 5, 1881; West Coast 



Shells, p. 27, 1892. 

 Murex foliatus Mart., Tryon, Man. Conch., Vol. II, p. 113, PI. XXXIV, figs. 370, 371, 373, 1880. 

 Plerorhytis folialus Mart., Cooper, Bull. No. 4, Cal. St. Min. Bureau, Part 3, 1894, p. 24. 



Shell small, broadly fusiform, with extended varices; spire elevated, subacute; whorls three 

 to four; varices three, widely e.Kpanded, foliated on anterior side: one prominent node on conve.x 

 surface of whorl between each set of varices; aperture subovate, with smooth outer and inner lip; 

 canal long, narrow, expanding anteriorly, generally covered by overgrowing lips. 



Dimensions. — Long. 35 mm.; lat. 21 mm.; body-whorl 26.5 mm.; aperture 2r mm.; 

 canal 10 mm. 



Distinguishable by the wing-like, foliated varices. The specimen described 

 was too poor to figure. 



Rare in the upper San Pedro series of San Pedro; one specimen found. 



Ziving. — Vancouver to Oregon (Carpenter): Sitka to Santa Barbara; Asia 

 (Cooper) . 



Pleistocene. — San Pedro (Arnold): Pnget Sound; San Uiego; Santa Barbara 

 Islands (Carpenter): San Joaquin Bay, Orange County (Bowers). 



242. Murex (Pterorhytis) nuttalli Conrad. 



Cerosioma nuttalli Con., Jour. Phil. Acad. Nat. Sci., Vol. VII, 1837, p. 264, PI. XX, fig. 22. Cpr., 

 Proc. Zool.Soc, 1856, p. 229; Brit. Assn. Rept, 1863, p. 663. Tryon, Struct, and Syst. 

 Conch., Vol. II, p. 105, PI. XLIII, fig. 8, 1883. Cooper, 7th Ann. Rept. Cal. St. Min., 

 1888, p. 233. Keep, West Coast Shells, p. 26, fig. 8, 1892. 



Plerorhytis nuttalli Con., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 215. 



Shell of medium size, heavy, thick; spire elevated, subacute; whorls four, convex, each with 

 three prominent varices, which are rather smooth behind, but showing their lamellar structure in 

 front; each varix is connected with the analogous varix on the preceding whorl, but the varices being 

 slightly less than one-third of a revolution apart cause the radiating ridges formed by the connected 

 varices to be spirally twisted; intervarical spaces prominently spirally ribbed, the ribs extending on 

 to the backs of the varices; seven or eight prominent spiral ribs on the body-whorls; aperture ellip- 

 tical; outer lip with eight or nine internal teeth, each corresponding to one of the external sulcations 

 of the body-whorl; sometimes with prominent tooth near anterior portion of outer lip; inner lip 

 smooth; canal rather short, covered; lower portion of columella expanded, rough, subpunctate. 



Dimensio?is.— Long. 65 mm.; lat. 34 mm.; body-whorl 50mm.; aperture 25 mm.; canal 

 14 mm. 



This species may be only a variety of /'. foliatus Mart. It is distinguishable 

 from the latter species by the greater prominence of its spiral sculpture, and its 

 lower varices. 



Rare in upper San Pedro series at Deadraan Island and Los Cerritos. 



Living. — Baulinas Bay to San Diego (Cooper). 

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



