[102] 



lip expanding, its extremities approaching and connected by a 

 large V-shaped tooth, there is also a large marginal basal tooth, 

 and a smaller tubercular tooth on the middle of the lip. White, 

 (bleached). 



Diam. 15, height 4.5 mill. 



Guaymas, Mexico. 



1 1 With three small marginal teeth on the outer lip. 



* * 



Mexican Species. 



11. DEBdalochila acute-dentata, W. G. Binney. 



Plate 10, figures 11, 13. 



Shell planorboid, ■whitish, smooth, whorls 6, very convex, spire 

 scarcely elevated, suture distinct ; the body -whorl oblique, in- 

 flated, deflected at the aperture and scrobiculate behind the lip ; 

 aperture small, ringent, lip circular, its extremities joined by a 

 broad angular tooth on the body whorl; there are three lip 

 teeth, one of them on the basal edge, perpendicular and short, 

 the other two are further within and form slight elongated hori- 

 zontal laminae, causing pits on the outer surface of the whorl. 



Diam. 14, alt. 4 mill. 



Cinaloa, on Mazatlan River, Mexico. 



12. Dsedalocliila Loisa, W. G. Binney. 



Plate 10, figures 12, 14. 



Shell planorboid, whitish, scarcely striate, suture slight ; 

 whorls 5, the last somewhat swollen, deflected channelled, and 

 with two pits behind the lips ; aperture ringent, 5-de^tate, one 

 on the parietal wall, large subtrigonal, connecting the lip ex- 

 tremities, the heavy lip slightly reflected, is armed with four 

 teeth, two of them short, stout and perpendicular on the edge 

 near the columella, while superior to them and farther within 

 are two short, slender horizontal lamina. 



Diam. 13, alt. 5 mill. 



Cinaloa, on Mazatlan River, Mexico. 



Perhaps only a variety of D. acute-dentata, in which an ad- 

 ditional' basal tooth takes the place of a scarcely tooth-like 

 elevation in the typical acute-dentata. 



