CUBAX SUBFAMILY CHONDROPOMIXAE — TORRE AND BARTSCH 223 



very slender, retractively slanting lamellar axial ribs between which 

 occasional finer threads appear. This, however, is not a regular ar- 

 rangement. Suture strongly constricted; periphery well rounded. 

 Base inflated, strongl}' rounded ; the inner Avail of the umbilicus is 

 marked by moderately strong, well-rounded, spiral threads, which 

 render the axial ribs somewhat serrulate at their junction. Aperture 

 broadly oval or subcircular. Peristome double, the inner projecting 

 slightly beyond the outer, and slightly expanded, smooth; the outer 

 broadly expanded, marked by concentric lines of growth, not in- 

 frequently transversely fluted. Breathing pore a little within the 

 peristome on the parietal wall near the posterior angle. Operculum 

 almost circular, multispiral, the inner four-fifths covered with a 

 rather strong calcareous deposit which gives it a corrugated appear- 

 ance, the corrugations having a protracted slant. 



This large species ranges through the Sierra de los Acostas, the 

 Sierra de San Carlos, the Sierra del Sumidero, the Sierra de Cabezas, 

 and the mogotes Ij'ing to the south thereof. 



It breaks up into three well-defined zoogeographic races to which 

 we are assigning subspecific rank. 



Distribution of the subspecies of C. (C.) inugnum is shown in 

 figure 77. 



KEY TO THE SUBSPECIES OF CHONDROPOMETES (CHONDPvOTHYROMA) MAGNUM 



Last whorl solute for one-tonth or more of a turn. 



Last part of last whorl decidedly deflected elisabethae 



Last part of last whorl not decidedly defected magnum 



Last whorl almost adnate signae 



CHONDROPOMETES (CHONDROTHYROMA) MAGNUM ELISABETHAE, new subspecies 



Plate 12. Figure 12 



Shell large, the early postnuclear whorls reddish, the rest buff, 

 marked by rather conspicuous interrupted spiral bands, which are 

 almost as broad as they are long and arranged in axial series. Peri- 

 stome Avith a reddish flush on the inner half. The last half of the 

 last whorl is decidedly solute. 



The type, U.S.N.M. no. 367749, was collected by Bermudez at 

 Isabel INIaria northeast of Sumidero. It has 4.5 whorls remaining 

 and measures : Length, 20.0 mm ; greater diameter, 18.0 mm ; lesser 

 diameter, 12.5 mm. 



CHONDROPOMETES (CHONDROTHYROMA) MAGNUM MAGNUM, new subspecies 



Plate 12, Figuke 13 



In this race the shell is large, ranging in color from pale brown 

 to reddish brown. The peristome may be white or reddish; the 

 outer ahvavs Avith concentric marks and usuallv Avith transA^erse 



