204 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



CHONDBOPOMA (CHONDBOPOMA) GBANIFERUM BUBNETENSE, new subspecies 



Plate 32, Figure 10 



This race, of which I collected quite a series on the west coast of 

 West Caicos, is the largest of the known forms of graniferum. All our 

 specimens were dead, hence white. The whorls were very inflated and 

 the spiral threads numerous, there being 14 between summit and suture 

 on the last whorl. The same type of sculpture continues over the periph- 

 ery and base. In this race the umbilicus is quite narrow and the parietal 

 wall of the aperture is almost adnate to the preceding turn, that is, the 

 solute portion is the least extensive of any of the known races. 



The type (U.S.N.M. No. 392363) has a little more than 4 whorls 

 remaining and measures : Length, 14.7 mm. ; greater diameter, 8.5 mm. ; 

 lesser diameter, 6.6 mm. 



U.S.N.M. No. 391850 contains 22 topotypes from the same source. 



CHONDBOPOMA (CHONDBOPOMA) GBANIFEBUM GBANIFERUM, new subspecies 



Plate 32, Figure 8 



We collected hundreds of specimens of this under rocks, in the arid 

 region of the south coast of Providenciales. It is the smallest of the 

 known races of graniferum and differs also from the others in having 

 the granulose sculpture less pronounced; in fact, it is decidedly reduced 

 on the last whorl. 



The type (U.S.N.M. No. 469138) has almost 4 whorls remaining 

 and measures : Length, 9.9 mm. ; greater diameter, 6.0 mm. ; lesser di- 

 ameter, 4.9 mm. 



U.S.N.M. No. 390974 contains 807 topotypes from the same source. 



U.S.N.M. No. 390181 contains 3 specimens from the southeast point 

 of Providenciales, Caicos Island group. 



CHONDBOPOMA (CHONDBOPOMA) GBANIFEBUM SAXICOLUM, new subspecies 



Plate 32, Figure 5 



This race we collected in large numbers under rocks at Kingston (Blue 

 Hill), Providenciales, that is, on the north coast of the island. It is 

 differentiated from the other races of graniferum by having very strongly 

 granulose sculpture, with the last whorl decidedly solute and the sum- 

 mit strongly nodulose. The axial ribs are much more closely spaced than 

 those of Chondropoma (Chondropoma) graniferum malcolmense, from 

 which it is also distinguished by its larger size. 



The type (U.S.N.M. No. 469137) has 4.3 whorls remaining and 

 measures: Length, 13.4 mm.; greater diameter, 7.6 mm.; lesser diame- 

 ter, 5.9 mm. 



U.S.N.M. No. 390815 contains 51 topotypes from the same source. 



U.S.N.M. No. 391597 contains 139 specimens collected by Bartsch 

 under rocks at Blue Hill, Kingston, Providenciales, Caicos Island Group. 



