340 CALIFOKNIA ACADEMY OF SCIENCES. 



399. Clypidella callomarginata Carpenter. 



"Clypidella callomarginata Cpr., Brit. Assn. Rept., 1866." Gabb, Pal. Cal., Vol. II, pp. 86, 124, 

 1869. Dall, Am. Jour. Conch., Vol. VII, 1872, p. 133, PI. XV, fig. 8. Cooper, 

 7th Ann. Rept. Cal St. Min., 1888, p. 235. Tryon, Man. Conch., Vol. XII, p. 197, 

 PI. XLIV, figs. 3, 4, 5; PI. LXI, figs. 1-5, 1890. 



Fissurellidaa callomarginata Cpr., Keep, West Coast Shells, p. 97, 1892. 



Lucapinella callomargiyiata Cpr., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 198. 



Shell elongate-ovate, conical, depressed; apical hole elongate-ovate, large, not central; 

 surface sculptured by alternating large and small radiating ridges, and prominent, concentric raised 

 lines; aperture elongate-ovate; margin crenulated, thickened. 



Ditnensio7is. — Long. 22 mm.; lat. 12 mm.; alt. 4.5 mm. 



The specimen described was identified by Dr. Dall. 



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

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



Living. — Lobitos to San Diego (Cooper). 



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



Genus Fissurella Bruguiire. 



Shell oval, conical, depressed, with the apex in front of the center, and perforated; surface 

 radiated or cancellated. 



Fissurella picta Gmel. is a characteristic species. 



400. Fissurella volcano Reeve. 



Fissurella volcano RvE., Icon. Conch., PI. IV, fig. 2, 1849. Shy., Thes. Conch., Vol. Ill, p. 192, 

 fig. 87. Cpr., Brit. Assn. Rept., 1863, p. 651. Gabb, Pal. Cal., Vol. II, p. 86, 1869. 

 Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 240. Tryon, Man. Conch., Vol. XII, 

 p. 156, PL LXII, figs. 16-18, 1890. Keep, West Coast Shells, p. 96, fig. 81, 1892. 

 Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 197. 



Shell oblong, conical, apical hole oblong, slightly anterior to center; numerous small radi- 

 ating ribs run down to the margin; margin smooth; alternating red and dark colored stripes radiate 

 from the apical hole; sloping surface straight. 



Dimensions. — Long. 27 mm.; lat. 19 mm.; alt. 10 mm. 



Distinguishable by the coloration, which is apparent in all the Pleistocene 

 specimens that have been examined. Much smaller than F. aspera Esch., which is 

 the only Pleistocene limpet it resembles. 



Rather common in the lower San Pedro series at Deadman Island and San 

 Pedro; and in the upper San Pedro series at Deadman Island, Los Cerritos, Crawfish 

 George's, and San Pedro. Found in the Pleistocene at Pacific Beach, San Diego. 



Living. — Santa Cruz to San Diego (Cooper). 



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

 (Arnold). 



