136 HELIX. 



H. HINDSII, Pfr. PI. 28, figs. 24-26. 



Depressed, orbicular, narrowly umbilicated, finely striated, diaph- 

 anous, shining, spire somewhat conical; whorls 5, slightly convex 

 above, more convex below, deflected at the aperture and constricted 

 behind it; aperture lunate, lip slightly reflected, its extremities united 

 on the parietal wall by a callus and a V-shaped tooth, the lip has two 

 basal teeth, and another on the right margin ; light corneous. 



Diam. 8 mill. 



Texas, Mexico. 



H. BICRURIS, Pfr. PL 28, figs. 21-23. 



Kimately umbilicated, thin, striulate, yellowish corneous, slightly 

 shining, suture submargined; whorls 5, somewhat convex, the last 

 scarcely deflected in front, base more convex, subconstricted behind 

 the aperture ; aperture with a two-pronged parietal tooth, two teeth 

 on the basal and one on the superior margin, lip white, shortly 

 reflected. Diam. 9 mill. 



Mexico. 

 H. VENTROSULA, Pfr. PL 28, fig. 27, 



Minutely perforated, thin, shining, suture well impressed ; whorls 

 5, but little convex and finely striate above, very convex and 

 smooth beneath, periphery subangulated, last whorl much constricted 

 behind the aperture; aperture with a V-shaped parietal tooth, two 

 white basal teeth and a large subtriangular lamella within the outer 

 margin; horn color. Diam. 8-11 mill. 



Texas and Mexico. 

 H. AVARA, Say. PL 28, figs. 28-30. 



Whorls 5, hirsute, slightly convex and coarsely . ribbed above, 

 convex below, and ribbed only for a short distance behind the 

 aperture, the balance of the base being nearly smooth ; base without 

 groove, showing a little more than one whorl, and with a minute 

 perforation; aperture with reflected lip, the extremities joined by a 

 parietal callus bearing a large V-shaped tooth, the base has an 

 oblique tooth, the right side a lamella, which is submarginal. 



Diam. 7 mill. 



Florida, Louisiana. 

 H. ESPILOCA, Ravenel. PL 28, figs. 31-33. 



Whorls 5, thin, costulate above, periphery subangulated, base 

 convex and finely striated, last whorl a little deflected in froirt and 

 constricted behind the aperture; base showing H whorls, the 

 umbilical region bounded by an angle; margin of aperture con- 



