ARNOLD — THE PALEONTOLOGY AND STKATIGEAPHY OF SAN PEDRO. 313 



352. Hipponyx turnens Carpenter. 



Hipponyx turnens CPR., Brit. Assn. Rept., 1863, p. 654; Ann. & Mag. Nat. Hist., 3rd Ser., 



Vol. XV, 1865, p. 181. 

 Capulus tiimens Cpr., Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 232. 



Shell of medium size, tumid, with oval base; apex distinct, small, sharp, curved to right 

 side, raised above margin; surface sculptured by numerous sharp, distinct, raised radiating lines and 

 less prominent lines of growth, which give the radiating lines a slightly granulose appearance; 

 aperture oval, slightly effuse, and finely crenulated on outer border. 



Dimensions. — Long, (including apex) 11.5 mm.; Jat. 10 mm.; alt. 5 mm. 



Distinguishable from H. antiquatus by its rather faint, regular sculpture, of 

 which the radiating lines are much more prominent than the concentric. 



One specimen from the lower San Pedro series of Deadman Island; also found 

 in lower San Pedro series at San Pedro; and in the upper San Pedro series at Dead- 

 man Island. Found also in the Pleistocene at Pacific Beach, San Diego. 



Living. — Monterey to San Diego and Islands (Cooper). 



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



Family LXXVIII. NATICID^. 

 Genus Natica {Adanson) Scopoli. 



Shell subglobular; spire slightly elevated; aperture half round; a spiral columellar callus 

 entering the umbilicus. 



Nation canrena Linn, is a characteristic species. 



Subgenus Cryptonatica Ball. 



Naticas with smooth calcareous operculum and an umbilicus entirely and smoothly filled 

 with callus. 



Type, Natica claiisa Brod. & Sowb. 



353. Natica (Cryptonatica) clausa Broderip & Sowerby. 



Plate X, Fig. 13. 



Natica clausa Brod. & Sby., Zool. Jour., Vol. IV, 1829, p. 360; Zool. Beechey's Voyage, p. 136, 

 PI. XXXIV, fig. 3; PI. XXXVII, fig. 6, 1839. Cpr., Brit. Assn. Rept., 1863, p. 661. 

 Gabb, Pal. Cal., Vol. II, p. 77, 1869. Tryon, Man. Conch., Vol. VIII, p. 30, PL IX, 

 figs. 65, 67-69, 73, i886. Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 253. Keep, 

 West Coast Shells, p. 46, 1892. 



Natica russa Gld., Proc. Bost. Soc. Nat. Hist., Vol. VII, 1859, p. 43; Otia, p. 109, 1862. Cpr., 

 Brit. Assn. Rept., 1863, p. 586. Cooper, Bull. No. 4, Cal. St. Min. Bureau, Part 3, 

 1894, p. 29. 



Shell of medium size, ovate-globular; spire only slightly elevated; whorls four, evenly 

 convex, though sometimes slightly shouldered; surface smooth except for fine incremental lines; 



( iO ) April 28, 1903. 



