328 CALIFOENIA ACADEMY OF SCIENCES. 



Shell conical, thin; spire elevated, subacute; whorls five or six, flat; ornamentation consists 

 of smooth keel on anterior part of whorl and row of nodes on posterior part next to suture; flat space 

 between these two smooth; both keel and flat surface nodose on anterior part of body-whorl; suture 

 very deep and narrow; body-whorl acutely angulated at base; base slightly convex, ornamented with 

 several alternating large and small nodose spiral ridges; aperture trapezoidal; outer lip thin, bulging 

 below; columella incrusted, and having two plications. 



Dime7isioHS. — Alt. 19 mm.; lat. 16 mm.; defl. 70 degrees. 



Distinguishable from the Cnlliostomm by the deep, narrow suture, large 

 aperture, with bulging lower part of outer lip, and plicated columella. 



Found in Pliocene of Deadman Island; one specimen from lower San Pedro 

 series of Deadman Island. 



Living. — Monterey (Cooper): San Pedro (Raymond). 



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



Pliocene. — San Pedro (Arnold). 



Genus Phorcus Risso. 



Shell conoidal, umbilicited; umbilicus cylindrical or infuiidibuliform; whorls frequently tuber- 

 culated above and with channeled suture; columella sometimes terminating in a tubercular tooth. 



Phorcus magus Linn, is a characteristic species. 



379. Phorcus pulligo Marlyn. 



Trochus pidligo Mart., Univ. Conch., PI. LXXVI, 1784. Philippi, Conch. Cab., p. 84, PI. XV, 



fig. 3. Fischer, Coq. Viv., p. 232, PI. LXXX, fig. i. 

 Phorcus pulligo Mart., Cpr., Brit. Assn. Rept., 1863, p. 653. Cooper, 7th Ann. Rept. Cal. St. 



Min., 1888, p. 259. 

 Clilorostoma pulligo Mart., =C marcidns Gi^D. {fide Tryon, Man. Conch., Vol. XI, p. 171, 



PI. XXVI, figs. 23, 24, 25, 1889). 



.Shell broadly conical; whorls five, flat, but somewhat obsoletely ribbed or bluntly nodose 

 in most specimens; surface shows extremeh' oblique lines of growth; suture distinct but not much 

 impressed; base flat and smooth, except for faint incremental lines; aperture subovate; lips not 

 thickened; umbilicus smooth, round and effuse. 



Dimensions. — Alt. 18 mm.; lat. 22 mm.; defl. 78 degrees. 



This shell is often confused with Chlorostoma mnntereyi, but may be distin- 

 guished from that species by its gradually expanding umbilicus, greater deflection, 

 and lack of spiral sculpture. Specimens of this .species were identified by Dr. Dall. 



Rather common in the upper San Pedro series of Crawfish George's. The 

 specimen figured is from the upper San Pedro series at Crawfish George's, and is 

 now in the collection of Delos Arnold. 



Living. — Sitka to San Pedro (Cooper.) 



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



