AKNOLD — THJ'^ PALIiONTOLOGY AND STUATICKAril Y OF SAN PEDRO. 201 



Rare in tlic; I'liocfiiL' aiul luwer .San i'udro series at Deadniaii l.slanil. The spo- 

 ciinon figured on Plate IX is tlio typo, which is from tlic lower Ran Pedio series at 

 Doadiuan Islinni, and is now in the Tnited States National Miiscnni; the specimen 

 lii^ured on Plate V is a stnnipy I'orni, wliirli might be calleil variety curia. 



Pltisloceue. — San Pedro (Arnold). 



Pliocene. — San Pedro (Arnold). 



165. Pleurotoma (Borsonia) dalli, sp. nov. 



P1.ATE VI, I'u.. 2. 



Shell small, fusiform; spire elevated; ape.x mammilliform; whorls eight, sharply angulatecl 

 a little anterior of middle; body-whorl less angulatecl than tliose of spire; posterior portion flat to 

 slightly concave, anterior portion slightly convex; first four whorls slightly nodose on angle; orna- 

 mentation consists of fine oblique, incremental lines which are conve.xly angulated posteriorly just 

 posterior to angle of whorl; sutiiie deeply impressed, distinct; aperture elongate-elliptical; outer lip 

 thin, arcuate anteriorly; inner lip incrusted; columdla slightly recurved, with one prominent plication 

 in middle of aperture; posterior sinus prominent; anterior sinus rather short. 



Dimensions. — Long. 23.5 mm.; lit. 9 mm.; hody-wliorl 13 mm.; aperture, including canal, 

 ID mm.; defl. 27 degrees. 



Di.5tingiiisliable by inaminillifonn ape.x, small deflection, sliarj)ly angulated, 

 smooth whorls, and plication on columella. Specimens pronounced new species by 

 Dr. Dal I. 



Rare in lower San Pedro series and Pliocene at Deadman Island. The speci- 

 men 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). 



166. Pleurotoma (Borsonia) hooveri, sp. nov. 



P1..1TE X, Fig. 1. 



Sliell small, fusiform; ape.x mammilliform; whorls Wvc or si.x, angulated slightly anterior to 

 middle; body-whorl less angul.ited than those of sjiire; surface smooth, e.xce[)t for incremental lines, 

 which are oblique, and angulated convcxly posteriorly a little above angle of whorl; suture deeply 

 impressed, distinct; aperture elliptical; outer lip thin, arcuate anteriorly below posterior sinus; inner 

 lip incrusted; columella incrusted, straight, with one prominent plication in middle of aperture; pos- 

 terior sinus shallow; anterior sinus short. 



Dimensions. — Long. 13 mm.; lat. 6.5 mm.; body-whorl 8. 2 mm.; aperture, including canal, 

 6.5 min.; defl. 50 degrees. 



Distinguishable from B. dnUii by greatly (lepres,sed spire, fewer whorls and 

 lack of nodes on apical whorls. Pronounced a new species by Dr. Dall. 



Rare in lower San Pedro series; two found at Deadman Island. The speci- 

 men figured is the type, which is from the lower San Pedro series at Deadmau 

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



Pleistocene. — San Pedro (Arnold). 



< 2G I March 12, IWJ. 



