GASTROPODA— EUOMPHALIDJE. 



665 



Fig. 918, A. Maclurea magna, a, b, c, upper, lower and side view of a character- 

 istic shell, X Yz > d-fi 3 views of large operculum, X X A.- (After Raymond.) 



whorl next adjoining ; upper surface almost flat, outer surface of 

 whorls with deep revolving grooves. Operculum with nucleus 

 near rim. 



Black River (?) of Ottawa River region in Canada, also European. 



Fig. 919. Maclurea bigsbyi, X %• Upper, profile and umbilical views. (After 



Ulrich, Pal. Minn.) 



