ARNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 271 



portion of the whorls, but fuse anteriorly before reaching suture; the ribs are bent slightly forward 

 near their posterior extremity; intercostal spaces deep, narrow; spiral sculpture fine but conspicu- 

 ous; the sutures are deeply impressed, with smooth sides, caused by the fusion of the ribs before 

 reaching the sutures; body-whorl rounded, smooth below, except for minute incremental lines and 

 spiral ornamentation. Aperture subquadrate; the outer lip joins the straight, somewhat revolute 

 columella at a right angle. 



Dimensions.— Y^on^. 5 mm ; lat. i.i mm.; altitude of body-whorl 1.4 mm. 



Tliis species somewhat resembles 2\ siearnsii, but is di.stinguisliable from that 

 species by the less number and greater prominence of the ribs, wliich in some cases 

 bend slightly forward near their posterior extremity. 2\ sbnilis was identified by 

 Dr. Dall; but the species was omitted from the text prepared by Dall and Bartsch. 



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

 common in the upper San Pedro series at San Pedro and Los Cerritos. 



Living. — Gulf of California to Panama (Carpenter). 



Pleistocene. — San Pedro (Arnold). 



286. Turbonilla (Strioturbonilla) stearnsii D. £ B., sp. nov. 



Plate II, Figs. 5 and 5a. 



Shell milk-white, rather stout; nuclear whorls two, small, helicoid, their axis being at right 

 angles to the axis of the post-nuclear whorls; post-nuclear whorls very slightly convex, almost 

 flattened, somewhat contracted at the base, and strongly shouldered at the summit, traversed by 

 eighteen to twenty-six oblique, flexuose, axial ribs, which render the summits of the whorls wavy; 

 intercostal spaces deep, terminating a little above the periphery, thus leaving a narrow, plain band 

 above the suture, as in T. torqicata siylina; the entire surface of the whorls is marked by numerous 

 faint, wavy, spiral .striations, which also ornament the otherwise plain basal portion of the last whorl; 

 suture well defined, slightly channeled; aperture subovate, anterior angle obtuse; outer lip thin, 

 joining the short, somewhat revolute columella in a gentle curve. 



Dimensions. — Long. 9.2 mm.; diam. 2.3 mm. 



The type, which has eleven and one-half post-nuclear whorls, is from the post- 

 Pliocene of San Diego. 



This species in a general waj'' resembles T. torquata stijlina, but differs from it 

 in being much more robust, of greater diameter throughout, and in having the fine, 

 wavy sculpture characteristic of the section. 



Turhonilla f Strioturbonilla J siearnsii occurs quite abundantly in the post- 

 Pliocene deposits at San Diego and San Pedro. It also occurs recent in the Gulf of 

 California. The name is proposed in honor of Dr. R. E. C. Stearns of Los Angeles, 

 who collected many sj^ecimens of this group. 



287. Turbonilla (Strioturbonilla) torquata Gould. 



Platk II, Figs. 4 and 4a. 



Chemnitzia torquata Gld., Bost. Jour. Nat. Hist., Vol. IV, 1853, p. 384, PI. XIV, fig. 16. 



Shell slender, solid, milk-white, entire suriace marked by faint, wavy, spiral striations; 

 nuclear whorls three, helicoid, their axis being at right angles to and to one side of the post-nuclear 



