﻿4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 59 



Except the pure white form (which may be a distinct species) all 

 the Yale specimens have well developed, or traceable, the following 

 characters: (i) A perforate axis with usually (when fully adult) a 

 wide funicular space behind the reflected lip at the entrance of the 

 perforation; (2) a more or less interrupted brown spiral band in 

 front of the suture 5(3) a very marked dark, often black spiral band, 

 which is covered by the advancing lip, immediately under the suture. 

 When nearly all the other brown markings are obsolete this single 

 band is very persistent, and is absent only when all the other spiral 

 dark bands, except the umbilical band, are absent; (4) a broad dark 

 band in the atrium of the umbilicus, the most persistent of all; (5) 

 between the subsutural and preceding antesutural bands on the last 

 whorl are several minor, narrower and less persistent bands, usually 

 more or less broken up into dots or patches. The normal number of 

 these seems to be three, but one is sometimes absent or fused with one 

 of the others. Between the subsutural and umbilical bands there are 

 one usually and sometimes two minor bands of which one is always 

 less strong than the other. All these bands may be absent or feeble, 

 but the umbilical band is usually traceable. The axial brown color- 

 ing is present in vertical streaks, when the shell is melanitic the color 

 seems to flow at the intersection of the spiral bands with these streaks 

 leading to an appearance which might be described as " strung tri- 

 angles." These, in very dark specimens, become more or less nebu- 

 lous or indistinctly limited. The spirals by themselves may fuse till 

 nearly the whole shell is dark colored. In Orbigny's varieties there 

 is no umbilical dark band and the shell is markedly white under the 

 pattern, while the Yale Expedition specimens tend to creamy or pale 

 buff rather than white. As a majority of the Yale specimens came 

 from the vicinity of Santa Ana, I propose to call this type variety 

 santanensis and restrict to Orbigny's form the designation poecilus 

 s. s. 



The former has, as has been indicated, a great variety of color 

 mutants, the more conspicuous of which may be enumerated as 

 follows : 



1. (variety?) percandidus Dall, nov. Shell pure white, seven- 

 whorled, perforate, surface somewhat rudely, axially striated, 

 with, on the last whorl, rather distant, somewhat irregular, 

 widely separated, minute axial ridges. Length of shell 32 ; of 

 aperture, 17; max. diameter of shell, 17 mm. 



Above Santa Ana, opposite Chinche, at 3500 feet elevation, 

 and above Ollantaytambo at 10,000 feet elevation. U. S. N. 

 Mus., No. 250245. 



