138 HELIX. 



lamella, basal margin twisted into a large oblique tooth; base 

 showing 1^ whorls, the umbilical region bounded by a carina. 



Diam. 13-15 mill. 



Florida. 

 Var. MICROFORMIS, Dall. 



Smaller, more closely whirled, umbilicus smaller and less per- 

 spective. Diam. 12 mill. 



H. CHIAPENSIS, Pfr. 



Narrowly umbilicated, somewhat solid, striated, shining, whitish 

 corneous, with a brownish band at the suture; whorls 5, somewhat 

 convex, the last deflected in front and turgid above, constricted 

 below, base inflated ; aperture large, diagonal, sinuately lunar, with 

 a small, thin, parietal tooth, peristome white, shortly reflected, 

 margins approaching, with a superior descending tooth, and an 

 obsolete denticle on the base. Diam. 1O5 mill. 



Chiapa, Mexico. 

 Unfigured. 



Subsection V, SCULPTARIA, Pfr. 1855. 



H. SCTJLPTURATA, Gray. PI. 25, figs. 69, 67, 68 ; PL 24, figs. 27, 28. 



Widely umbilicated, closely costulate, the interstices reticulately 

 striate, whitish, spire planulate ; whorls 5, slightly convex, the last 

 constricted in front on the base; aperture circular, with an entering 

 parietal lamella and two teeth on the right margin, peristome 

 subexpanded above, reflected below. Diam. 8 mill. 



Damara, So. Africa. 

 Var. COLLARIS, Pfr. PL 24, figs. 27, 28. 



This form has 4} whorls with channeled suture, the last acutely, 

 creiiately carinate, solute in front, corneous white. 



Var. DAMARENSIS, H. Adams, figs. 67, 68. 



Very closely covered with capillary strise, whitish fulvous above, 

 whitish below, with a light fulvous band on the periphery, the 

 whorls are 6, the last suddenly decending in front, the periphery 

 ribbed-carinated, the aperture has the parietal lamina and three 

 obtuse lip teeth. 



Section III. STROBILA, Morse, 1864. 

 H. LABYRINTHTCA, Say. PL 29, figs. 44-48. 



Obtuse conic, yellowish brown; whorls 6, closely ribbed above, 

 more slightly so below, suture well impressed; lip thickened, somewhat 

 reflected, with two revolving laminae upon the base, not visible from 



