HELIX-OBBA. 235 



Group of H. merarcha (typical Neocepolis). 



Shell globose, with elevated spire, and narrow, slowly-widening 

 whorls, the last deflexed in front. Aperture small, truncate-rounded, 

 the lip reflexed all around, its ends joined by a stout callus. Colu- 

 mella dilated, thickened, and obtusely toothed within. A strong 

 fold within the outer wall, marked outside by a deep pit. Type 

 Helix merarcha Mabille. 



This shell has very much the aspect of the Neotropical section 

 Cepolis, but belongs, I do not doubt, in the vicinity of Obba. 



The value of the internal fold on the outer wall of the aperture 

 as a group character is not very great. 



Examples of a similar structure are found in H. subtussulcata, of 

 the section Jeanneretia ; H. pellisserpentis, of the group Solaropsis ; 

 H. porcellana and H. endoptycha, of the section Planispira; H. 

 duclosiana of the section Plagioptycha ; and teeth with corres- 

 ponding pits outside are characteristic of the sections Cepolis and 

 Stegodera. The first four groups named include also species with- 

 out an internal tooth. 



Besides possessing a palatal fold, Neocepolis merarcha differs 

 from If. campanula, etc., in the narrow, closely coiled whorls, 

 stronger parietal callus, and different columella. 



H. MERARCHA Mabille. PI. 32, figs. 42, 43, 44, 45. 



Narrowly, almost closed umbilicate,globose-conoidal, solid, opaque, 

 (probably brown, the only specimen known being destitute of 

 cuticle and whitish) ; surface closely, regularly plicate-striate, 

 smoother beneath ; apical two whorls smooth, shining ; spire convex 

 in outline, elevated, dome-shaped ; apex obtuse ; sutures scarcely 

 impressed ; whorls 6, very slowly widening, the upper ones not con- 

 vex, the last two somewhat convex above. The periphery is slightly 

 angled on the last whorl ; the base is scarcely convex on the first 

 half, but its latter part is inflated, gibbous. It is somewhat con- 

 stricted behind the basal lip, very deeply deflexed anteriorly. 

 There is a deep groove or scrobiculation immediately below the 

 periphery a short distance behind the lip, which corresponds to a 

 callous lamella inside the outer lip. The aperture is very oblique, 

 small, truncate-rounded, livid inside ; peristome thick, expanded, 

 subreflexed, flesh-colored, columellar margin dilated, thickened and 



