228 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



ribs on the first, 57 on the second, 66 on the third, and 28 on the last 

 third of a turn of the remaining whorls. Of spiral threads there are 6 

 on the first, 9 on the second, 12 on the third, 8 on the base, and 8 on 

 the umbilical wall. 



The type (U.S.N. M. No. 390327) has 3.3 whorls remaining and 

 measures : Length, 9.0 mm. ; greater diameter, 5.3 mm. ; lesser diameter, 

 4.8 mm. 



U.S.N.M. No. 391 5 12 contains 5 topotypes from the same source. 



OPISTHOSIPHON (OPISTHOSIPHON) ELEUTHERAENSIS, new species 



Shell rather large, elongate-conic, varying from sooty flesh-color to 

 rose-red to pale brown, the early whorls being darker than the rest ; the 

 whorls are also marked by slender, interrupted spiral bands of brown. 

 Nuclear whorls decollated. Postnuclear whorls moderately well rounded, 

 very narrowly shouldered, and marked by slender, vertical axial threads, 

 which are very closely spaced, being separated by spaces scarcely as 

 wide as the ribs. At more or less regular intervals, some of these riblets 

 develop into prominent hollow cusps at the summit, which crenulate the 

 suture. The spiral sculpture is obsolete on tlie spire ; a wavy aspect of the 

 ribs merely indicates its presence. Suture moderately constricted. Pe- 

 riphery well rounded. Base moderately long, well rounded, openly um- 

 bilicated, and marked by the continuation of the axial riblets and feeble 

 spiral threads that are a little stronger within the umbilicus. The last 

 whorl is not solute. Aperture oval; peristome double, the outer broadly 

 expanded, a little more on the inner lip than the outer, marked by a 

 series of concentric lamellae ; at the posterior angle the outer peristome 

 forms a feeble auricle which is adnate to the siphon immediately behind 

 it; inner peristome slightly exserted and slightly reflected. Operculum 

 typically opisthosiphonid. 



The close axial ribbing and feeble spiral sculpture combined with the 

 adnate last whorl will readily distinguish this from the other Opisthosi- 

 phons. 



The species appears confined to the island of Eleuthera. I am recog- 

 nizing two subspecies as follows : 



KEY TO THE SUBSPECIES OF OPISTHOSIPHON (OPISTHOSIPHON) 

 BLEUTHERAENSIS 



Shell soiled flesh-color pallidus 



Shell rose-color eleutheraensis 



OPISTHOSIPHON (OPISTHOSIPHON) EI.EtJTHEBAENSI8 PALLIDUS, 



new subspecies 



Plate 36, Figure 8 



Shell varying from soiled flesh-color to pale brown ; the early whorls 

 are darker than the rest; the early whorls are also marked by slender 

 interrupted spiral bands of brown, while the peristome is white. Of the 



