HISPANIOLAN AND BAHAMAN ANNULARIIDAE 205 



CHONDKOPOMA (CHONDROPOMA) GBANIFEBUM MAr.COL,MENSE, new subspecies 



Plate 32, Figure 7 



We collected this race at Malcolm Bay on the northwest coast of 

 Providenciales. It most nearly resembles Chondropoma (Chondropoma) 

 graniferum saxicoliim but differs from it in its smaller size and much 

 more distantly spaced axial ribs. 



The type (U.S.N.M. No. 469136) has 4.8 whorls remaining and meas- 

 ures: Length, 9.7 mm.; greater diameter, 7.0 mm.; lesser diameter, 

 5.2 mm. 



U.S.N.M. No. 390210 contains 7 topotypes from the same source. 



CHONDBOPOIHA (CHONDBOPOaLA) MABIGUANICOLUM, new species 



Shell of medium size, elongate-ovate, varying in color from flesh- 

 color to pale yellow ground color, unicolor or banded with interrupted 

 lines of brown; the elements composing these are also arranged in axial 

 series and are present on both spire and base. Nuclear whorls about 

 1.5, forming an inconspicuous apex, which is slightly flattened at the 

 summit. The nuclear whorls are smooth, except the last portion of the 

 last turn, which shows the beginning of slender axial hairlike threads 

 that gradually develop into the postnuclear axial sculpture. The post- 

 nuclear whorls are very strongly inflated, rounded, and marked by 

 slender, slightly retractively curved axial riblets. The spiral sculpture 

 consists of slender threads equaling the riblets in strength, which they 

 render granulose at their junction. Suture channeled for almost half a 

 turn behind the aperture ; the rest feebly shouldered. Periphery inflated, 

 strongly rounded. Base rather short, strongly rounded, marked like the 

 spire by the continuation of the axial riblets and spiral threads. Umbili- 

 cus narrowly open. The last whorl is adnate to the preceding turn. The 

 aperture is broadly ovate. Peristome double, the outer and inner fused, 

 showing the separate nature only on the parietal wall and at the auricle 

 at the posterior angle. Operculum typically chondropomoid. 



This species is peculiar to Mariguana Island and the little cay south 

 of it known as Booby Cay. 



KEY TO THE SUBSPECIES OF CHONDROPOMA (CHONDROPOMA) 

 MARIGUANICOLUM 



Granulation very pronounced mariguanicolum 



Granulation less pronounced stolidum 



OHONDBOPOMA (CHONDBOPOMA) MABIGUANICOLUM MARIGUANICOL,rM, 



new subspecies 



Plate 34, Figure 4 



This race, which occupies Mariguana Island, is one of the most vari- 

 able species, as far as size is concerned, specimens three times the size 

 of the smallest being found in the same locality. The race is character- 

 ized by having a very pronounced granular sculpture, with rather feeble 

 denticulations at the summit, a very narrow umbilicus, and with the 

 parietal wall of the aperture adnate to the preceding turn. 



