ARNOLD — THE PALEONTOLOGY AND STRATlGlUPHY OF SAN PEDRO. '251 



251. Trophon (Boreotrophon) multicostatus Eschseholtz. 



Pi.ATK VI, Fig. 9. 



Miirex mullicostahis EscH., Zool. Atlas, \'ol. II, p. 11, PL IX, fig. 4, 1829. Kuster, Afurex, 



p. 45, PI. XVI II, fig.s. 5 and 6, 1837. 

 Trophon inullicostaius EscH., H. & A. Adams, Gen. Rec. Moll., Vol. i. p. 77. Cpr., Rrit. Assn. 



Rept., 1863, p. 663 (in jiart). Tryon, Man. Concli., Vol. II, p. 141, PI. XXXI, fig. 



316, 1880. Cooper, 7tli Ann. Rept. Cai. St. Min., 18S8, p. 269 (in part). Keep, 



West Coast Shells, p. 21, 1S92 (in part). 



Shell small, tiisiform; whorls five, angular above, with twelve to fourteen raised varices; no 

 spiral sculpture; aperture subelliptical; outer lip not effuse; inner lip smooth; canal short, slightly 

 curved. 



Dimensions. — Long. 10.5 mm.; lat. 4.5 mm.; body-whorl 7 mm.; aperture, including canal, 

 5 mm.; canal i mm.; defl. 40 degrees. 



The shell described is a small one. Distinguishable from T. (jvacilh by 

 having larger number of varices, le.ss prominent varices, more slender shell, a less 

 effuse outer lip, and less sharply angulated whorls. Identified as "7'. multicostatus 

 var.?" by Dr. Dall. 



Rare in the lower San Pedro series at Deadman Island, and in upper San 

 Pedro series at San Pedro. The specimen figured is from the lower San Pedro series 

 at Deadman Island, and is now in the collection of Delos Arnold. 



Living. — Sitka to Monterey; circumpolar (Cooper). 



Pleistocene. — Santa Barbara (Cooper): San Pedro (Arnold). 



252. Trophon (Boreotrophon) pedroana, sp. nov. 



Plate VL Fig. P2. 



Shell small, elongate-fusiform, thin; spire elevated, acute; whorls si.x, convex, with very 

 slight angle about one-third width from posterior margin; body-whorl slightly ventricose; whorls 

 ornamented with about fourteen slightly raised, rounded transverse ridges, and two faint spiral 

 ridges, one of which is on the angle of whorl; suture deeply impressed, distinct; aperture semiovate; 

 outer lip thin, not effuse; inner lip smooth; columella long and slender, smootli; canal long, narrow, 

 nearly straight. 



Dimensions. — Long. 12 mm.; lat. 4.8 mm.; body-whorl 9 mm.; aperture, including canal, 

 7 mm.; canal 3 mm.; defl. 35 degrees. 



The thinnest, most delicate of the Irophons of this locality. Distinguishable 

 from var. pr(ecitrsor by thinness, less angulation of whorl.s, less prominence of 

 sculpture, and simple outer lip; distinguishable from T. !<calarifonais by its thinness, 

 narrowness, and spiral lines; distinguishable from T. disparilis Dall by smaller size, 

 more numerous whorls, and more i)roniinent transverse sculpture. 



Pronounced a new species by Dr. Dall, who also says that it is near 7\ dis- 

 parilis, whicii has been dredged at Gray's Harbor, Alaska. 



Rather common in the lower San Pedro series at San Pedio and Deadman 

 Island; found also in upper San Podro series at Crawfish George's. The specimen 



