198 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



U.S.N.M, No. 536682 contains 2 specimens from the Smith Collec- 

 tion from Great Inagua. 



We gathered this species in large numbers in various parts of Great 

 Inagua, the type locality, both along the northern shore line and the 

 interior. It shows considerable variation, but this occurs in each locality, 

 so that there are no isolated races to be considered. Dall's Rhytidopoma 

 euploca and Clench's Chondropoma russelli are merely variants of the 

 main theme. It is not surprising that Dall and Clench, dealing probably 

 with selected material, should have been misled as to the distinctness of 

 these two. 



The decidedly reduced sculpture will distinguish this from all the 

 other species of Chondrops. 



Subgenus Chondropomorus Henderson and Bartsch 



1920. Chondropomorus Henderson and Bartsch, Proc. U. S. Nat. Mus., vol. 58, 

 p. 61. 



Shell ovate ; marked by both axial and spiral threads, the axial threads 

 being gathered into tufts at the summits of the whorls. 



Type species: Cyclostoma dentatiim Sd^y =^ Chondropoma (Chondro- 

 pomorus) dentatum (Say), 



KEY TO THE BAHAMAN SPBCIES OF CHONDROPOMORUS 



Axial ribs very slender and closely spaced erroneum 



Axial ribs coarse canescens 



CHONDROPOMA (CHONDROPOMOBrS) ERRONETJar, new species 



Plate 32, Figure 11 



Decollated shell elongate-ovate, all but the last of the remaining post- 

 nuclear whorls chestnut-brown; the last horn-colored. The whorls are 

 marked between the summit and periphery by three spiral rows of 

 elongate brov/n spots, having their long axis parallel with the spiral 

 sculpture. These spots are also arranged in axial series; an additional 

 row of similar marks is present at a little distance below the periphery, 

 and several feebly expressed ones occur near the umbilicus. On the dark 

 early whorls these brown markings are rendered indistinct by the dark 

 general color. The peristome is horn-colored, while the dark markings 

 on the outside of the last whorl show on the inside of the aperture. The 

 postnuclear whorls are moderately rounded and marked by sublamellar 

 axial ribs, which become regularly more closely spaced with the increas- 

 ing whorls. Of these 257 are present on the last whorl in the type. These 

 riblets at irregular intervals become fused at the summit where they 

 form the nodules that characterize the subgenus. In addition to the axial 

 ribs, the whorls are marked by low, rounded spiral threads, of which 

 II are present between the summit and the periphery. These threads 

 render the axial ribs slightly wavy and slightly nodulose at their junc- 

 tions. Suture rather deeply channeled. Periphery well rounded. Base 



