16 PALAEONTOLOGY OF CALIFORNIA. 



shell; the generic relations must therefore be left in doubt until further speci- 

 mens are found exhibiting more of the details of the under surface. In some of 

 its details, the present species resembles P. gibberosum living on the coast, but its 

 strongly biangular form will serve to distinguish it. 



TURCICA, H. and A. Ad. 



Subgen. PTYCHOSTYLIS, Gabb. 



{Id., Gabb; Proc. Cal. Acad. Nat. ScL, Jan. 1865, p. 187.) 



Animal unknown. Shell resembling Thalotla and Calliostoma; 

 conical, not umbilieated; spire elevated; aperture subquadrate, 

 internally pearly; columella truncated, bearing an oblique fold 

 on the anterior end and one above; outer lip and base acute, 

 slightly thickened behind; umbilical region slightly excavated, 

 and covered by a thin expansion of the inner lip. 



T. (P.) COFFEA. 



PL 3, Fig. 27. 



(P. cofca, Gabb ; Proc. Cal. Acad. Nat. Sci., Jan. 1865, p. 187.) 



Shell conical; spire elevated; sides flattened; whorls seven, 

 first one smooth and round, succeeding ones subangulated at the 

 lower margin, obliquely flattened above; body whorl convexly 

 subtruncated below; suture channelled. Surface marked by a 

 row of comparatively large tubercles on the upper margin of the 

 whorl, adjoining the suture, and by a variable number of revolv- 

 ing, finely tubercular ribs on the sides; there are usually from 

 six to ten on the side, and about the same number on the under 

 surface of the body whorl; these tubercles are very small, and 

 are generally arranged in an irregular quincunx; the under sur- 

 face of the body whorl, just below the angle, is marked by a 

 deep revolving groove. Aperture subquadrate; outer lip and 

 base acute; inner lip narrowly emarginate beyond the truncated 

 end of the columella. 



