88 University of Michigan 



PLATE XIV 



Helicina and Ampullaria. 



Figure i. Helicina zepliyrina. Basal view with operculum in place, 

 as in aestivating individuals, to show the sinuation of the basal lip 

 and the crack left between the operculum and the lip. 



Figure 2. Ampullaria patula catcmacensis. Type specimen. 



Figure 3. A. p. cateiiiacensis. Exterior view of operculum. 



Figure 4. A. p. catemacensis. Interior view of operculum. 



