CUBAX SUBFAMILY CHONDROPOMINAE TORRE AND BARTSCH 213 



Axial dark band behind peristome absent. 



Shell red or reddish sagebieni 



Shell not red or reddish. 



Shell white or yellowish concolor 



Operculum white. 

 Shell red. 



Axial ribs rather distantly spaced magnum 



Axial ribs rather closely spaced saccharinum 



Shell white or buff. 



Shell banded segregatum 



Shell not banded scopulorum 



Chondropometes {Chondrothyroma) heJUssimum has not been con- 

 sidered in this key for want of operculum. It has the size of C. (C.) 

 exquisUtim but lacks the dark axial band behind the peristome and 

 has much lower and closer spaced axial ribs. 



CHONDROPOIVIETES (CHONDROTHYROMA) EXIMIUM, new species 



Shell large, resembling C. {€'.) magnmn in shape, but with the 

 axial ribs much finer and closer spaced and the operculum red. 



Three races of this species are known. They occupy parts of the 

 Sierra de los Acostas, Sierra San Carlos, and the Sierra del Quemado. 



Distribution of the subspecies of C. {C.) eximium is show^n in 

 figure 73. 



KEY TO THE SUBSPECIES OF CHONDROPOMETES (CHONDROTHYROMA) EXIMIUM 



Spiral markings absent eximium 



Spiral markings not absent. 



Spiral markings confined to the varicial bands angusticulum 



Spiral markings not confined to the varicial bands malleatum 



CHONDROPOMETES (CHONDROTHYROMA) EXIMIUM EXIMIUM, new subspecies 



Plate 10, Figuke 4 

 Shell large, pale yellowish, which is also the color of the peristome, 

 the inner being a little paler than the expanded portion, without spiral 

 bands. Axial ribs closely spaced. Spiral threads on the umbilical wall 

 very faint. Operculum red. 



The type, U.S.N.M. no. 351925, was collected by Wright at Isabel 

 Maria. It has 4 whorls remaining and measures : Length. 23.2 mm ; 

 greater diameter, 22.3 mm ; lesser diameter, 15.6 mm. 



CHONDROPOMETES (CHONDROTHYROMA) EXIMIUM ANGUSTICULUM, new subspecies 



Plate 10, Figure 5 

 Shell pale yellow with obsolete spiral bands, which are intensified 

 at irregular intervals, which coincide in axial series. Peristome white ; 

 umbilical wall marked by obsolete spiral threads. 



