144 HELIX-ISOMERIA. 



peculiar, flat deposit appressed to the convexity of the base, contin- 

 tied from the callous basal lip. (Martens.) 



Alt. 29, diam. maj. 55, min. 45 mill. 



Aperture, (incl. perist.) diam. 39, alt. 2H mill. 



Aperture, (excl. perist.) diam. 20, alt 14 mill. 



Cerro Pelado, La Plata, New Genada. (2300 meters' alt.) 



H. (Isomeria) scalena MARTENS, Conchol. Mittheil. ii, p. 171, t. 

 31, f. 1-3 (1881-'85). 



In lacking teeth this shell resembles somewhat the West Indian 

 Caracolus. The umbilicus is closed by the same peculiar callous 

 continuation of the baso-columellar lip described under If. cymatodes 

 and seen in various species of Isomeria. 



H. MEOBAMBENSIS Pfeiffer. 



Covered umbilicate, conoid-depressed, solid, subdistantly rugose- 

 striate, all over minutely granulated, cinnamon-colored ; spire conoid- 

 convex, obtuse ; whorls 5, nearly plane, slowly widening, the last 

 descending anteriorly ; periphery subcarinated, above and below 

 more convex; aperture very oblique, tetragonal-lunar; peristome 

 white, reflexed, margins joined by a callous, columellar margin 

 dilated, adnate, straight, unidentate on the right. (Pfeiffer.) 

 Alt. 15, diam. maj. 32, min. 26 mill. 



Moyobamba, Peru. 



H. meobambensis PFR., Proc. Zool. Soc. Lond. 1856, p. 328 ; 

 Monographia iv, p. 243. 



An unfigured species, known only by Pfeiffer's diagnosis, above 

 translated. 



H. ATRATA Pfeiffer. PI. 44, figs. 3, 4. 



Shell nearly covered umbilicate, depressed, solid, striate and 

 minutely granulate, greenish-black ; spire a little elevated, apex 

 obtuse ; whorls 5, nearly plane, sensibly widening, the last carinated, 

 turgid above anteriorly and deflexed ; .base swollen, sack-like to- 

 ward the aperture ; aperture very oblique, subtrigonal-lunar ; 

 peristome thick, white, reflexed all around, its terminations joined by 

 a thick callous, right margin furnished above the base with an 

 obtuse conical tooth. (Pfeiffer.) 



Alt. 19, diam. maj. 44, min. 37 mill. 



Mts. of Ecuador and Colombia. 



