138 HELIX-ISOMERIA. 



Helix faunus PHILIPPI, Zeitschrift fiir Malakozoologie 1851, p. 

 29. PFEIFFER, in Conchyl. Cab., p. 416, 1. 148, f. 1-3 ; Monographia 

 iii, p. 257. 



Differs from H. oreas in the thicker shell, less distinctly granulate, 

 more costulate ; the absence of a parietal tooth, and the much thicker 

 lip. (Phil.} 



I refer to faunus as a variety, a pair of shells before me which agree 

 in most respects with Philippi's diagnosis and figures. They may be 

 described as follows : 



VAR. RITCHIEANA Pilsbry. PL 62, figs. 14-17. 



Umbilicate, large, solid, rather thick, deep chocolate colored, ear- 

 inated at the periphery; surface shining, striate and minutely, 

 densely granulate ; spire dome-shaped, low, obtuse ; sutures scarcely 

 impressed, except the last half of the outer one, which is impressed ; 

 whorls 5i, scarcely convex, gradually widening, the last not so wide 

 as in H. oreas, only slightly dilated transversely, a little narrower on 

 its last third, less carinated there, and more convex beneath ; but in 

 all these respects less strongly characterized than H. oreas. Toward 

 the aperture the whorl is rather deeply deflexed, and behind the 

 peristome it is constricted ; there is more or less malleation on the 

 last whorl below the periphery, and on one specimen a little above 

 it. The aperture is subquadrate, purplish-brown inside with a satiny 

 sheen, and very oblique ; peristome white, reflected, thickened, its 

 face polished and convex, upper margin arched, lower margin 

 thickened, nearly straight, its inner edge slightly undulating or wavy ; 

 outer margin with a narrow, slightly compressed tooth ; umbilicus 

 5 to 6 mill, in diameter, partly covered by the dilated columella ; 

 parietal wall with a narrow white callous connecting the terminations 

 of peristome. 



Alt. 26, diam. maj. 52, min. 43 mill. 



Alt. 21, diam. maj. 51, min. 43 mill. 



Aperture, breadth 28, alt. 22 mill. (Inclusive of peristome.) 



Pichincha, N.-W. Ecuador. 



Named in honor of Mr. JOHN RITCHIE JR., of Boston, Mass. The 

 figures show the variation in elevation to which the species is subject. 

 The aperture has a curved profile like that shown in the figure of 

 H. Fordiana on the same plate, but less markedly so. 



