HELIX. 125 



mersed ; whorls 10?, narrow, slightly convex, the last much wider, 

 subdepressed, scarcely descending in front, all wider below ; umbili- 

 cus more than half the diameter of the base ; aperture subdiagonal, 

 the lip scarcely expanded, white margined within. Diam. 25 mill. 



Moyobamba, Peru. 



H. decagyra, Martens, and H. helicycloides, Pfr. (figs. 78-80), are 

 synonyms ; the latter a minor variety. 



H. HELIGMOIDEA, Orbigny. PL 25, figs. 81-83. 



Very widely umbilicated, smooth, yellowish corneous ; whorls 9, 

 slightly convex; aperture obliquely semioval, sinuous, peristome 

 shortly reflected, dentate within, the extremities connected by a 

 dentiform callus. Diam. 13 mill. 



Guayaquil, Co lumbia. 



H. CALCULINA, Pfr. PL 25, figs. 84-86. 



Very widely umbilicated, thin, striulate, yellowish corneous, 

 obsoletely strigate with chestnut ; whorls 8 J, convex, very narrow,, 

 the last not descending, superiorly and basally subangulated ; lip 

 simple, straight. Diam. 10 mill. 



Sab. unknown. 



First described as H. calculus, Pfr., a name preoccupied by Lowe. 



H. POLYCYCLA, Morelet. PL 25, figs. 87-89. 



Very widely umbilicated, closely striate, slightly shining, light 

 corneous ; whorls 7, convex, with deep suture, slowly increasing ; 

 aperture diagonal, obliquely semilunar, lip simple, straight, sinuate 

 above. Diam. 15 mill. 



Peru. 



H. TORTILIS, Morelet. PL 25, figs. 90-92. 



Very widely umbilicated, thin, diaphanous, light corneous, 

 slightly shining ; whorls 7, slightly convex, narrow, with deep 

 suture ; aperture obliquely rounded-lunar, lip straight, shortly 

 rounded above. Diam. 11 mill. 



Urubamba, Peru. 



H. DECAGYRA, Phil. PL 25, figs. 93-95. 



Widely umbilicated, thin, scarcely striated, spire nearly plane, or 

 slightly convex, yellowish corneous; whorls 11, narrow, the last 

 depressed at the aperture ; aperture somewhat oblique, the lip thin 

 acute. Diam. 10'5 mill. 



Peru. 



