134 HELIX. 



H. COULONI, Shuttleworth. PL 28, fig. 98. 



Narrowly, perviously umbilicated, sharply striulate, light corneous; 

 whorls 6, somewhat convex, slowly increasing, the last gibbously 

 constricted at the aperture and suddenly deflected ; peristome white, 

 reflected, parietal wall with a pliciform tooth, the external part 

 with a strong tooth, the basal with a smaller one. 



Diam. 10 mill. 



Vera Cruz. Mexico. 



H. ACUTEDENTATA, Binney. PI. 28, figs. 99-4. 



Shell whitish, smooth; whorls 6, very convex, suture distinct; 

 body whorl inflated, oblique, deflected at the aperture and scrobicu- 

 late behind the lip; aperture small, ringent, lip-extremities joined 

 by a broad angular parietal tooth ; there are three lip-teeth, one on 

 the basal margin, erect and short, the other two are farther within 

 and form slight elongated horizontal laminae, marked by pits on 

 the outer whorl. Diam. 14 mill. 



Near Mazatlan, Mexico. 

 Var. LOISA, Binney. Figs. 2-4. 



A little higher, the aperture with five teeth, . the basal margin 

 unequally bidentate, other teeth as in the type. 



H. BEHRII, Gabb. PI. 28, figs. 5-7. 



Shell planorboid, coarsely ridged above, striate below ; whorls 5, 

 convex, subangular at the periphery, very much deflected in front 

 and constricted behind the aperture ; umbilicus broad, with a minute 

 central perforation ; aperture rounded, lip expanding, its extremities 

 approaching and connected by a large V-shaped parietal tooth, there 

 are also a large marginal basal tooth and a smaller tubercle on the 

 middle of the outer margin. Diam. 15 mill. 



Guaymas, Mexico. 



H. JACKSONI, Bland. PL 28, figs. 8-11. 



Depressed, striate, smooth beneath, narrowly umbilicated ; whorls 

 8, slightly convex, deflected in front, and contracted behind the lip ; 

 aperture oblique, lunate, lip thick, briefly reflected, its extremities 

 joined by a V-shaped parietal tooth, basal margin with a strong 

 oblique sinuous fold, right margin with a deeply seated tooth ; dark 

 brown, shining, lip brownish. Diam. 7 mill. 



Fort Gibson, Indian Territory; Springfield, Mo.; Arkansas. 



H. HIPPOCREPIS, Pfr. PL 28, figs. 12, 13. 



Shell solid, opaque, depressed, with flattened spire and impressed 

 suture; whorls 5? scarcely convex above, abruptly deflected in 



