HELIX-ISOMERIA. 151 



rather convex, slowly widening, the last angulate at periphery, 

 narrower a little on its last third, the cariiia becoming obsolete there 

 and the base more convex ; gradually, rather deeply deflexed at the 

 aperture, and constricted behind the peristome ; aperture very 

 oblique, livid inside, subtrigonal-rounded ; peristome liver-brown, 

 reflexed, not nearly so much thickened as in H. juno, upper margin 

 arcuate, with a thickening on its face above the position of the 

 periphery, outer margin bearing a compressed acute tooth a trifle 

 below the position of periphery, basal margin straightened, bearing 

 a square tooth in the middle, its columellar margin expanded over 

 or nearly over the umbilicus and appressed ; parietal callous brown, 

 narrow. 



Alt. 18, diam. maj. 34, min. 30 mill. 



Alt. 18, diam. maj. 31, min. 27 mill. 



Alt. 20, diam. maj. 38, min. 32 mill. 



Ecuador. 



H. cequator ia PFR. Proc. Zool. Soc. 1860, p. 133, t. 50, f. 6 ; Mai. 

 Bliit. 1860, p. 236 ; Mouographia, v, p. 314. MILLER, Mai. Blat. 

 1878, p. 170. 



Allied to H. stoltzmanni, equestrata, and less so to H.juno. The 

 upper margin of peristome has a more or less developed callous or 

 swelling on its face, well shown in the figure. The whorls of the 

 spire are convex, as in H. juno. 



H. EQUESTRATA Moricand. PI. 48, figs. 45, 46. 



Nearly covered umbilicate, subglobose, solid, striate, very minutely 

 granulate, chestnut-colored ; spire little elevated, apex obtuse ; sut- 

 ures impressed ; whorls 5, scarcely convex, regularly increasing, the 

 last somewhat carinated, descending; aperture very oblique, tet- 

 ragonal; peristome thick, white, reflexed, margins joined by a thick 

 callous, provided with an obtuse conical tooth. (J/oric.) 



Alt. 17, diam. maj. 36, min. 31 mill. 



Moyobamba, Peru. 



H. equestrata MORIC. in Rev. et Mag. Zool. 1858, p. 449, t. 13, f. 

 1. PFR. Monographia, v, p. 315. 



Known only by the original descripton and figure. It seems 

 closely allied to H. tequatoria, but the lip is w r hite, and the base 

 shows no denticle in the figure. 



