HISPANIOLAN AND BAHAMAN ANNULARIIDAE 193 



KEY TO THE SUBSPECIES OF CHONDROPOMA (CHONDROPS) BIFORME 



Spiral threads on spire crowded. 



Spaces between axial ribs and spiral threads thimble-pitted. 



Pits round sulaense 



Pits elongate biforme 



Spiral threads on spire not crowded. 

 Shell heavy and robust. 



Axial sculpture rather fine cottonense 



Axial sculpture coarser arenarium 



Shell not heavy or robust. 



Whorls rather high between summit and suture. 



Axial sculpture very fine bellense 



Axial sculpture coarser gambelense 



Whorls not high between summit and suture. 



Axial sculpture very fine salarium 



Axial sculpture coarser neyi 



CHONDBOPOMA (CHONDROPS) BIFOBME SULAENSE, new subspecies 



Plate 33, Figure 11 



Of this race I collected a large series of specimens on Booby Cay at 

 the east end of Mariguana Island. It differs from the other races in 

 having the whorls inflated and the axial riblets rather strong. The com- 

 bination of the axial riblets with the spiral threads produces a thimble- 

 pitted pattern, but here the pits are nearly rounded, the long axis 

 coinciding with the axial sculpture. 



The type (U.S.N.M. No. 390450) has 4.5 whorls remaining and 

 measures: Length, 10.6 mm.; greater diameter, 5.0 mm.; lesser diame- 

 ter, 4.3 mm. 



U.S.N.M. No. 391637 contains 329 topotypes from the same source. 



In the sculptural pattern it most nearly resembles typical C. (C.) 

 biforme biforme, but differs in having much less inflated whorls. 



CHONDBOPOMA (CHONDBOP8) BIFOBME BIFOBME Pfeiffer 



Plate 33, Figure 8 

 1858. Chondropoma biforme Pfeiffer, Malakozool. Blatter, vol. 5, p. 143. 



In this race, which comes from Grand Turk Island, Bahama, the 

 whorls are inflated, the spiral cords moderately strong, rather closely 

 crowded and crossed by numerous slender threads, the spaces enclosed 

 between the axial and spiral sculpture forming elongate pits. 



The specimen described and figured (U.S.N.M. No. 391927), one of 

 129 collected by Bartsch, has 4.3 whorls remaining and measures: 

 Length, 11.7 mm.; greater diameter, 5.7 mm.; lesser diameter, 5.2 mm. 



U.S.N.M. No. 362840 contains 8 specimens intercepted in Philadelphia 

 by the Federal Horticultural Board in soil about cactus plants coming 

 from Turk Island. 



In the strength of the axial riblets it resembles most closely Chon- 

 dropoma (Chondrops) biforme sulaense. 



