204 CALIFORNIA ACADEMY OF SCIENCES [Proc. 30 Ser. 



spaces, and flattened above; spire very small, but with distinct suture; spiral 

 lines not showing within. 



Three specimens in the collections of the California Acad- 

 emy of Sciences are apparently referable to this northern 

 species, and this determination is supported by other evi- 

 dence and faunal resemblances. 



The species has a near relative in the Pliocene of San 

 Fernando as seen in 6". planicostnni Gabb, but the form of 

 the shell is evidently different. 



Occurrence. — Lower Miocene beds of Kern River. 



Nassa arnoldi n. sp. 



Plate XVI, Figs. 70 and 71. 



Shell small, acutely ovate; spire moderately elevated, bearing 5 whorls; 

 aperture circular, outer lip always bordered by a thickened varex; columella 

 short, bearing only a slight, or no sulcus; surface ornamented by spiral and 

 longitudinal ridges forming a reticulation as in the young of N. perpengtiis 

 Hds. 



This species differs from N . perpengnis in its smaller size, 

 more regular and symmetrical form, shorter columella, the 

 absent, or much reduced sulcus, and the bucal border which 

 appears on all of the specimens that have been found. 



Occurrence. — This species occurs with the preceding in 

 the Lower Miocene beds of Kern River. 



Crepidula praerupta Conrad. 



Plate XVI, Figs. 68 and 69. 



C. praerupta Conrad, U. S. Expl. Exped. (Wilkes) pi. xix, figs. 9, 9a, loa, 

 \ob; text p. 727. 



Shell of medium size, i-i>^ inches long; strongly curved; aperture 

 elliptical, or ovate; surface marked by irregular lines of growth. 



Occurrence. — The species is found abundantly in the Lower 



Miocene beds of Kern River. 



Pleurotoma (Clathurella) dumblei n. sp. 



Plate XV, Figs. 60 and 61. 



Shell small or medium in size, i-ij^ inches long; spire high; whorls 6 or 

 more, convex; aperture simple, ovate, inner lip uncalloused; canal very 



