Plate 15. 



Fig. 1. Durania manuelcnsis Stephenson. View of the type specimen, natural 

 size, from the upper part of the San Felipe formation, Las Flores hacienda, 

 from an arroyo 34 kilometers west by north of Manuel station, showing the 

 surface sculpture on the half of the shell in front of the anterior siphonal 

 area. Cat. No. 32506, U.S.N.M. Page 12. 



Fig. 2. View of the type specimen of D. mamielensis, showing the siphonal areas 

 (E) and (S) and tbe surface sculpture back of these areas. Page 12. 



