356 PROCEEDINGS OF THE NATIONAL. MUSEUM vol. 85 



the outer expanded and reflected, forming a conspicuous auricle at 

 the posterior angle and adnate to the preceding turn on the parietal 

 wall; the inner slightly exserted above the outer and also slightly 

 reflected. Operculum thin, corneous, paucispiral, with submarginal 

 nucleus, the outside covered with a thin deposit of fine calcareous 

 granules. 



This species a])pears to range from the mouth of Yateras River in 

 Oriente, west through the Guantanamo Bay shorelines. We are 

 recognizing three subspecies. 



KEY TO THE SUBSPECIES OF CHONDROPOMA (CHONDROPOMA) MARGINALBUM 



Denticles at the summit narrow and closely crowded marginalbum 



Denticles at the summit not narrow or closely crowded. 



Sculpture coarse , guantanamense 



Sculpture not coarse subguantanamense 



CHONDROPOMA (CHONDROPOMA) MARGINABLUM MARGINABLUM (Gundlach) Pfeiffer 



Plate 31, Figure 2 



1859. Cyclostoma marginalhum (Gundlach) Pfeiffeb, Malakozool. Blatter, 

 vol. 6, pp. 75, 76. 



This is the rose-colored race in which the axial riblets terminate 

 as slender narrow, closely spaced denticles at the summit. The axial 

 riblets are less strongly expressed and narrower than in the other 

 two races. It comes from Caimanera. 



The specimen figured, U.S.N.M. no. 493190, has about 4 whorls 

 remaining and measures: Length, 18.0 mm; greater diameter, 9.9 

 mm ; lesser diameter, 8.2 mm. 



CHONDROPOMA (CHONDROPOMA) MARGINALBUM GUANTANAMENSE, new subspecies 



Plate 31, Figure 1 



This race occupies the lowland point on the west side of the en- 

 trance to Guantanamo Bay. It is a small race with very close sculp- 

 ture, comparatively speaking, and with strong denticulations at the 

 summit. 



The type, U.S.N.M. no. 367784, has 3.3 whorls remaining and meas- 

 ures: Length, 14.0 mm; greater diameter, 8.2 mm; lesser diameter, 

 7.0 mm. 



CHONDROPOMA (CHONDROPOMA) MARGINALBUM SUBGUANTANAMENSE, new 



sabspecies 



Plate 31, Figure 3 



This is a small race that appears to extend over the shoreline of 

 the eastern portion of Guantanamo Bay, being found on the various 



