ARNOLD — THE lULEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 279 



[S. D.J Turbonilla (Pyrgolampros) lowei, var. pedroana I), d />., var. uuv. 



Platk II, Fu:s. 3 and 3a. 



Shell similar to T. Icncri, both in general form and sculpture, hut more robust, broader and 

 less attenuate; nuclear whorls three, half immersed; post-nuclear whorls with ribs of more uniform 

 size, not crowded and enfeebled on the early whorls as in T. /otcv/; basal portion of the whorls of a 

 darker color than the upper, causing the e.xposed portion of the whorls to ai>pear banded above the 

 suture; whorls faintly shouldered, otherwise as in T. lowei. 



Dimensions. — Long. 7 mm.; diam. 2.3 mm. 



The type lias nine post-nuclear whorls. Specimen.^ from Victoria, H. C, arc 

 still broader. One of seven post-nuclear whorls measures: lon<^. 5.5 mm.; diam. 

 2.1 mm. The northern specimens are also somewhat li<;htGr in color. This variety 

 is found living from Victoria, B. C, to San Diego, and occurs fos.sil in the post- 

 Pliocene beds at San Diego. 



298. Turbonilla (Pyrgolampros) arnoldi D. A.- B., sp. uov. 



Pu-VTE I, Fig. 7. 



Shell whitish, robust, more or less inflated; nuclear whorls decollated; post-nuclear whorls 

 flattened, somewhat contracted at base, and slightly outcurved at the summit, traversed by about 

 twenty-two to twenty-eight more or less irregular axial ribs, slanting slightly toward the aperture, 

 and which extend less prominently over the well-rounded periphery of the last whorl to the umbilical 

 region; suture deep, subchanneled, somewhat undulate; the entire surface of the whorls is covered 

 with tine, very closely placed, wavy, spiral striations; last whorl somewhat produced; aperture large, 

 subovate, with a thin outer lip, which is decidedly effuse at base, and meets the somewhat oblique and 

 revolute columella in a broad curve. 



Dimensio7is. — Long. 7.6 mm.; diam. 2.3 mm. 



The specimen figured has eight post-nuclear whorls. 



This species so far has only been reported from tlic post-Pliocene deposits 

 of Deadman Island. It is named in honor of Mr. Ralph Arnold, of Pasadena, 

 California. 



299. Turbonilla (Pyrgolampros) gibbosa Carpenter. 



Pl.ATK I, FiCS. 2 AND 2a. 



Chemnitzia gibbosa Ci>r., Cat. Maz. Sliells, p. 430, No. 525, 1857. 



Shell inflated, robust, broad and stumpy, of light, fulvous coloration; nuclear whorls deeply 

 immersed, very slightly exjjosed at the tip, their axis apparently being at a right angle to the axis of 

 the later whorls; post-nuclear whorls flattened, somewhat contracted at the periphery and rounded 

 at the summit, traversed by about sixteen to twenty-four broad, coarse, irregularly slanting axial 

 ribs, which extend over the inflated periphery of the last whorl to the umbilical region, appearing less 

 prominent on the base; the entire surface of the shell is covered by very minute, close, spiral 

 striation; suture subchanneled and wavy; aperture ovate, outer lip thin, joining the twisted and 

 revolute columella in a broad curve. 



DiTnensions. — Long. 5.6 mm.; diam. 2.1 mm. 



The specimen figured has seven post-nuclear whorls. 



