HELIX-AMPELITA. 29 



slight indications of spiral lines. The spire is convex, low, very 

 obtuse, apex planorboid, light brown ; suture evenly but slightly 

 impressed. Whorls 4, rapidly widening, a trifle convex, the last very 

 obtusely angular at periphery, a little descending in front, the base 

 with a rather flattened aspect. Aperture very oblique ; bluish and 

 shiny inside ; peristome narrowly expanded all around, bluish, edged 

 with brown, the upper lip moderately arched, basal lip straight, 

 columella short, making nearly a right angle with the basal lip ; 

 parietal wall covered by a very thin transparent wash of callus. 

 Umbilicus moderate, deeply penetrating, funnel-shaped. 



Alt. 16, greater diam. 31, lesser 26 mill. 



Other specimens are a little more elevated, and of a straw yellow, 

 with a narrow deep chestnut sutural band, another wider one at and 

 above the periphery, the umbilicus also dark inside (see figs. 61, 62 

 of pi. 4). The dark zones are not so sharply defined as shown in the 

 figure, but fade into the ground-color at the edges. 



H. BASIZONA Mousson. PI. 9, figs. 22, 23. 



Shell moderately umbilicated, depressed, obtusely conical, solid, 

 irregularly striated, somewhat shining, deep brown. Spire depressed 

 conical, regular ; summit very obtuse, denuded, gray ; suture 

 moderately distinct. Whorls 5, moderately widening, the earlier 

 nearly plane, the following somewhat convex, the last scarcely de- 

 scending, obtusely angulated, less convex beneath, narrowly round- 

 ing at the perforating umbilicus, with a broad yellow zone in the 

 middle of the base, umbilicus dark. Aperture oblique (45 degrees 

 with the axis), obtusely triangular, violet-gray inside; peristome 

 narrowly expanded and reflexed, whitish, the margins much con- 

 verging, joined by a transparent, thin callus ; upper margin curved, 

 basal nearly straight, suddenly ascending at the columella, not in- 

 vading the umbilicus. (Mouss.) 



Alt. 22, greater diam. 35, lesser 31 mill. 



Madagascar. 



Ampelita basizona MOUSSON, Journ. de Conchy 1. 1882, p. 41. 



This is a form closely allied to H. calypso Pfr. The surface is 

 dark all over except on the base, which has a broad zone of straw- 

 yellow ; the earlier whorls lose their epidermis, becoming whitish. 

 The single specimen before me is smaller than- Mousson's types, and 

 has nearly the entire base occupied by the broad yellow zone. 



