ARNOLD— THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 191 



Specimen identified by Dr. Dall. 



One specimen from the Pliocene at Deadman Island which is figured, and is 

 now in the collection of Delos Arnold. 



Living. — Vancouver Island to San Diego (Cooper). 



Pleistocene. — San Diego (Cooper). 



Pliocene. — San Diego well (Cooper): San Pedro (Arnold). 



149. Tornatina harpa Dall. 



Tornatijia harpa Dall, Am. Jour. Conch., Vol. VII, 1872, p. 136, PI. XV, fig. 11. Keep, West 

 Coast Shells, p. 125, 1892. 



Shell small, white, of four and a half whorls; tabulate and sharply carinate above, character- 

 ized by sharp grooves and raised lines, parallel with the lines of growth, which extend half over the 

 whorls and become obsolete anteriorly; apex mammillated, minute globular, prominent; suture 

 canaliculated; anterior portion of the last whorl smooth; last whorl slightly narrower above; aperture 

 long, narrow, effuse below, with a deep, narrow sinus at the suture; columellar plait obsolete in the 

 adult, rather prominent in the young shells; carina intersected by the grooves and slightly dentate. 



Dimensiojis. — Long. 6 mm.; lat. 3 mm. 



Easily distinguishable by the longitudinal sculpture on the upper half of the 

 last whorl. 



Eare in the upper and lower San Pedro series at San Pedro. Found in upper 

 San Pedro series at Spanish Bight, San Diego. 



Living. — Monterey (Dall): Catalina Island, 10 fathoms (Arnold, 1901). 



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



Genus Volvula A. Adams. 



Shell subcylindrical, attenuated to a point posteriorly, to which the narrow aperture extends; 

 spire concealed; outer lip sharp; columella with an obsolete anterior plication. 



Volvula acuminator Brug. is a characteristic species. 



150. Volvula cylindrica Carpenter. 



Platb IV. Fig. 2. 



Volvula cylindrica Cpr., Brit. Assn. Rept., 1863, p. 647; Ann. & Mag. Nat. Hist., 3rd Ser., Vol. XV, 

 1865, p. 380. Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 270. Williamson, 

 Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 195. Tryon, Man. Conch., Vol. XV, 

 1892, p. 239. 



Shell small, cylindrical; flattened in middle and with margin almost parallel, swelling out 

 anteriorly; suddenly narrowed behind, running out into short, narrow, umbilicated point; aperture 

 length of shell; very narrow posteriorly, gradually broadening into subovate opening at anterior 

 end; surface smooth, except for faint lines of growth parallel to margin of shell. 



Dimensions. — Long. 11 mm.; maximum diam. 4.5 mm. 



Resembles Cylichna alba, but has an extended umbilical point. Dall (Trans. 

 Wagner Inst. Sci., Vol. Ill, Part 1, 1890, p. 16) mentions a ''Volvula cylindrica 



