CRETACEOUS FOSSILS. 125 



state, suture impressed, linear, angle of body whorl crenulated ; 

 surface marked by numerous line, revolving lines; lip thin, 

 broadly rounded, most prominent in the middle. In the adult 

 shell, the surface-markings and suture are obliterated by a heavy 

 incrustation, which covers the spire and body volution. Aperture 

 broad behind, narrowed in advance; outer lip provided on the 

 margin with a broad, heavy callus above and a smaller one below, 

 with a narrow, subangular sinus between them ; between the 

 upper callus and the body whorl there is a broad, deep emar- 

 gination; below, the margin rapidly retreats towards the canal, 

 which is strongly curved forwards in the form of a blunt hook. 

 Viewed from the back, the upper margin of the lip presents a 

 thick, rounded callus, commencing at the club-shaped extremity, 

 and which, curving upwards, merges into the general contour of 

 the shell, on the upper surface of the body whorl. 



Figures, natural size. 



Locality: In the hills southwest of Martinez (Division A.). The strong hook- 

 like canal, and the notch in the outer lip, will at once distinguish this from tho 

 other four known species of the genus. 



P. MAXUBRIATUS, II. S. 

 PI. 29, Fig. 229. 



Shell small, rather thin; spire moderately high ; whorls six, 

 rounded; suture distinct. Mouth long, narrow, very acute pos- 

 teriorly; canal wide, straight, not very deeply notched; outer lip 

 with a square callus, prolonged above into a long, slightly curved 

 hook; the notches above and below the origin of the callus are 

 well marked, the lower one being somewhat variable; the margin 

 of the lip is thickened along its whole length; inner lip heavily 

 incrusted, the layer being prolonged so as to cover the whole 

 ventral face of the shell to the apex. Surface marked by nume- 

 rous sinuous ribs, extending from the suture about two-thirds of 

 the distance towards the anterior end. 



Figures, natural size. 



Locality: Cottonwood Creek. Sisk'you County. 



