HISPANIOLAN AND BAHAMAN ANNULARIIDAE 203 



Spire not decidedly granulose. 

 Suture channeled. 



Suture channeled on more turns than the last necopium 



Suture not channeled on more turns than the last. 



Last whorl adnate glabratum 



Last whorl slightly solute hjalmarsoni 



Suture not channeled planicolum 



Chondropoma (Chondropoma) inaguense (Weinland) is not included 

 in this key. 



CHONDROPOMA (CHONDROPOMA) GBANIFKBUM, new speciea 



Shell of medium size, when complete elongate-ovate, when truncated 

 ovate; varying in color from white to pale yellow in ground color, uni- 

 color or marked with interrupted spiral bands of brown, the elements 

 of which are also usually arranged in axial series. Nuclear whorls about 

 2, forming a blunt apex, well rounded ; the early ones finely granulose, 

 the last portion showing the beginning of closely spaced, axial, hairlike 

 threads, which increase in strength to develop eventually into axial post- 

 nuclear ribs. The postnuclear whorls are strongly rounded and marked by 

 numerous rather closely spaced axial riblets, which vary in strength and 

 spacing in the different races. In C. (C.) graniferum graniferum they 

 become weakened on the last turn. These riblets form little nodules at 

 the summit, which they strongly denticulate. The spiral sculpture con- 

 sists of slender threads also varying somewhat in strength and number 

 in the different races. The junction of these with the axial riblets forms 

 conspicuous granules. Suture moderately constricted, channeled for 

 about one-tenth of the last turn. Periphery inflated, strongly rounded. 

 The base is moderately long, strongly rounded, openly umbilicated, the 

 umbilicus being rather wide in all but Chondropoma (Chondropoma) 

 graniferum burnctense. The last whorl is solute for some distance. The 

 aperture is broadly ovate, auriculate at the posterior angle. Peristome 

 double; the two coextensive on the outer and basal lip and only differ- 

 entiated on the parietal wall, particularly so at the posterior angle. Oper- 

 culum typically chondropomoid. 



This species ranges through the keys of the northwestern end of the 

 Caicos atoll. Its strongly rounded whorls with the conspicuous granular 

 sculpture and the solute last whorl will differentiate it from the other 

 species. 



The following key will help to distinguish the races: 



KEY TO THE SUBSPECIES OF CETONDROPOMA (CHONDROPOMA) GRANIFERUM 



Umbilicus narrow burnetense 



Umbilicus not narrow. 



Posterior angle of aperture strongly auriculate. 



Axial ribs distantly spaced graniferum 



Axial ribs not distantly spaced saxicolum 



Posterior angle of aperture not strongly auriculate malcolmense 



