330 CALIFOUNIA ACADKMY OF SCIENCES. 



Rail' in the Pliocene of Doadmaii Ishiiid, ami in tiie lower Ran Pedro 

 series of Deadinan Island and San Pedro; eoninion in the npper San Pedro series of 

 Deadnian Islanil, 8an Petiro, Ivos Ccrritos, and ( rawfisli ( Jeorjje's. F(»niid in the 

 Pleistocene at Spanish Bigiit, and in ihi' Pliocene at Pacilic Beacii, San Diego. 



Living. — Straits of Fnea to San Diego (Cooper). 



Pleistocene. — San Pedro to San Diego (C'ooj)er): Sun Pedro; San Diego 

 (Arnold). 



Pliocene. — San Pedro; San Diego (Arnold). 



382. Calliostoma costatum Mart an. 



Trochus costaliis Mart., Univ. Concli., Fl. X, fig. 3, 1784. Piiilii'im, Concli. Cab., p. 275, 



PI. XL, fig. 8. 

 Calliostoma coslalum Mart., Cpr., Brit. Assn. Rept., 1863, p. 652. Gabb, Pal. Cal., Vol. II, 



p. 83, 1S69. Cooper, 7th Ann. Rept. Cal. St. .Min., 1888, p. 231. Tryon, Man. 



Conch., Vol. XI, p. 362, PI. XVI, fig.s. 6, 9; PI. XVIII, fi^. 16, 1889. Keep, West 



Coast Shells, p. 81, fig. 66, 1892. Williamson, Proc. U. S. Nat. Mus., Vol. XV, 



1892, PI. XXII, fig. I. 

 Zizyphinus filosHS Wood, Reeve, Conch. Icon., fig. 27. 



Shell turbinated, thick; whorls five, convex, and ornamented with about eight, almost equally 

 prominent, spiral ridges; fine oblique incremental lines visible on most specimens; suture deeply 

 impressed; base slightly conve.\, ornamented same as whorls; outer lip slightly efTuse; columella 

 thickened and incrusted. 



Dimensions. — .•\lt 22 mm.; Lit. 20 mm.; defl. 70 degrees. 



Distinguishable by the even convexity of the whorls, inunerous, comparatively 

 smooth, spii;al ridges, and thickness of the sliell, which is unusual for a member of 

 this genus. 



Rare in the lower San Pedro series of Deadman Island and San Pedro; and 

 in tlie upper San Pedro series of Crawfish George's, Los Cerritos, and San Pedro. 

 Found in the Pleistocene at Pacific Beach, San Diego. 



Living. — Sitka to San Diego (Cooper). 



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

 (Arnold). 



Pliocene. — San Fernando, Los Angeles County (Cooper). 



383. Calliostoma gemmulatum Carpenter. 



Calliostoma gemmulatum Cpr., Brit. Assn. Rept., 1863, ]). 653; Proc. Cal. Acad. .Sci., Vol. Ill, 

 1864, p. 2(5. Cooper, 7ih Ann. Rept. Cal. St. Min , 1888, p. 231. Trvon, Man. 

 Conch., Vol. XI, p. 371, Pi. LXVII, fig. 54, 1889. Keep, West Coa.st Shells, p. 81, 

 1892. Williamson, Proc. U. S. Nat. Mas., Vol. XV, 1892, PI. XXII, fig. 3. 



Spire more acute than in other species of the genus; whorls six to seven, concave above, 

 convex below; convex part has two or three rows of granular spiral ridges; concave surface orna- 

 mented with a few fine granular spiral ridges; suture indistinct; base flat, marked by several smooth 

 spiral ridges; aperture circular. 



Dime7isimis. — Alt. 18 mm.; lat. 15 mm.; defl. 46 degrees. 



