AKNOLD — THE PALEONTOLOGY AND STUATIGKAPHY OF SAN PEDRO. 237 



This unique species is distinguishable by its smooth upper whorls, and sculp- 

 tured body-whorl. Pronounced a variety of 0. solidula Rve. by Dr. Dall. 



The shell of which this form is a variety is found living on the coast of Ecua- 

 dor, South America. The type is the only specimen that has been found in the 

 upper San Pedro series at San Pedro; it is figured, and is now in the United States 

 National Museum. 



Pleistocene. — San Pedro (Arnold). 



Subgenus Anachis II. tt A. Adams. 



Shell oval-fusiform, longitudinally ribbed; spire elevated; aperture narrow; columella 

 straight; outer lip nearly straight, crenulated within. 



Anachis rugosa Sowerby is a characteristic species. 



228. Columbella (Anachis) minima, sp. uov. 



Plate IX, Pig. 8. 



Shell small, resembles a young /iw^A/wa corrugata but much slenderer; surface sculptured 

 by numerous transverse ridges and fine spiral sulcations; whorls six, shouldered above as in Amphissa 

 versicolor; aperture subquadrate; outer lip nearly straight; pillar straight, spirally striated. 



Dimensions. — Long. 6 mm.; lat. 2.4 mm.; body-whorl 3.5 mm.; aperture 2.2 mm.; defl. 

 28 degrees. 



Distinguishable from Amplix>is,a corrugata by slenderer form, more shouldered 

 whorls and less wavy transverse ridges. Pronounced a new sjjecies of Anacliis, by 

 Dr. Dall. 



Type from upper San Pedro series of San Pedro; rare. The specimen 

 figured is the type, which is now in the United States National Museum. 



Pleistocene. — San Pedro (Arnold). 



Subgenus .ffisopus Gould. 



Shell fusiform, gibbous, broadly truncate in front; aperture lunate, with a posterior callous 

 on the body; columella smooth, vitreous; suture abnormally arcuate near the aperture. 



Type, u^sopus japonicus Gould. 



229. Columbella (.Ssopus) chrysalloidea Carpenter. 



Plate V, Fio. 6. 



Amycla chrysalloidea Ci'R., Brit. Assn. Rept., 1863, p. 612; Proc. Cal. Acad. Sci., Vol. Ill, 1S64, 



p. 223. 

 Columbella chrysalloidea Cpr., Trvon, Man. Conch., Vol. V, p. 135, PI. L, fig. 42, 1883. 

 Astyris chrysalloidea Cpr., Keep, West Coast Shells, p. 36, 1892. 

 Columbella {yEsopus) chrysalloidea Cpr., Williamson, Proc. U- S. Nat. Mus., Vol. XV, 1892, p. 213. 



Shell small, with general elongate-elliptical outline, or chrysalis-shaped; spire elevated, sub- 

 acute; whorls six, very slightly convex; surface marked by delicate spiral ridges and furrows; 



