ARNOLD -THE PALEONTOLOGY AND STKATIGKAPHY OF SAN PEDRO. 207 



176. Drillia merriami, sp. no v. 



Plate VIII, Fig. 7. 



Shell small, fusiform, rather thin; ape.x blunt; whorls seven, somewhat angular, with about 

 fourteen slightly oblique, prominent, rather sharp transverse ridges; these ridges are most prominent 

 on angle of whorl, and become obsolete near anterior margin and at about one-third width of whorl 

 from posterior margin; a narrow sutural band occupies upper one third of whorl; incremental lines 

 visible; suture deeply impressed, distinct; body-whorl somewhat ventricose and narrowed anteriorly, 

 with transverse ribs sometimes obsolete; aperture broadly elliptical, narrowed anteriorly to a promi- 

 nent sinus; posterior sinus small, near suture; outer lip arcuate, thin; columella smooth. 



Ditnenst07is. — Long. 14.2 mm.; lat. 5.2 mm.; body-whorl 7.6 mm.; aperture, including 

 canal, 6 mm.; canal 1.5 mm.; defl. 31 degrees. 



Thi.9 species somewhat resembles Borsonia hartschi, bat may be distinguished 

 by lack of columellar plait, longer but less oblique transverse ridges, and narrower 

 sutural band. Distinguishable from I), hemphilli by lack of spiral sulcations, less 

 oblique ribs, much longer body-whorl, and much more prominent canal. Dis- 

 tinguishable from D. torosa by lack of sjiiral lines, narrower sutural band, less convex 

 whorls, and more and longer ribs. This species is said by Dr. Dall to be near the 

 Panama species B. pallida Sby. Named in honor of Dr. John C. Merriam, Pro- 

 fessor of Paleontology in the University of California, who has assisted the writer in 

 many ways in the jDreparation of this paper. 



Rare in Pliocene and lower San Pedro series of Deadman Island. The 

 specimen figured is the type, which is from the lower San Pedro series at Deadman 

 Island, and is now in the United States National Museum. 



Pleistocene. — San Pedro (Arnold). 



Pliocene. — San Pedro (Arnold). 



177, Drillia montereyensis Stearns. 



Pkurotoma (Drillia) mojiiereyensis Stearns, Proc. Cal. Acad. Sci., Vol. V, 1873, p. 80, PI. I, 

 fig. 21. Tryon, Man. Conch., Vol. VI, p. 184, PI. XII, fig. 30, 1884. 



Shell small, elongate, slender; seven moderately rounded whorls, upper portion of volutions 

 concavely angulated and ornamented with fine spiral ribs and furrows; middle of upper whorls and 

 upper part of body- whorl displaying fifteen equidistant, longitudinal, nodose, slightly oblique ribs; 

 on the smaller volutions of the spire a puckering at and following the suture suggests a second 

 indistinct series of nodules; aperture less than half the length of shell; canal short; posterior sinus 

 rather broad, rounded and of moderate depth. 



Dimensions. — Long. 15 mm.; lat. 6 mm.; body-whorl 8.4 mm.; aperture 6 mm.; defl. 

 22 degrees. 



Resembles a large D. liemphilli in shape, but has a very distinctive orna- 

 mentation. 



Rare in the lower San Pedro series at Deadman Island; of the two specimens 

 found, one was obtained by Mrs. Oldroyd. 



Living. — Monterey (Stearns). 



Pleistocene. — San Pedro (Oldroyd; Arnold). 



