128 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



of which 20 are present between the summit and the periphery, 15 on 

 the base, and 16 on the umbilical wall. The junctions of the axial ribs 

 and spiral threads form oval nodules whose long axis is parallel with 

 the axial sculpture. Suture narrowly channeled, rendered crenulated by 

 the axial ribs at the summit. Periphery inflated, well rounded. Base 

 openly umbilicated. The last whorl solute for about one-third of a turn. 

 Aperture broadly oval; peristome double, the outer moderately strongly 

 expanded, of about the same width except on the parietal wall where it 

 is narrow; the inner strongly expanded and reflected over the outer, 

 with which it coincides on the outer and basal lip. Operculum with the 

 nucleus halfway between marginal and central having a very fragile 

 pseudolamella, which does not extend to the outer reaches of the whorls 

 of the basal chondroid plate and which shows the connecting riblets 

 between the basal chondroid plate and the pseudolamella. 



The specimen described and figured (U.S.N.M. No. 504082) is one 

 collected by Eyerdam about one-half mile north of Miragoane, Haiti. It 

 has 4 whorls remaining and measures : Height, 33.4 mm. ; greater di- 

 ameter, 21.6 mm.; lesser diameter, 16.0 mm. In measurements and 

 general form this specimen coincides well with the original figure and 

 description of labco. 



A second specimen (U.S.N.M. No. 504083), also collected by Eyer- 

 dam I mile north of Miragoane, shows in the peristome formation even 

 a closer resemblance to the original figure of laheo. It has 4.5 whorls 

 remaining and measures : Height, 37.7 mm. ; greater diameter, 25.5 mm. ; 

 lesser diameter, 18.8 mm. 



SALLEPOMA, new genus 



Shell varying from elongate-ovate to cylindroconic. Nuclear whorls 

 about 2, microscopically granulose, Postnuclear whorls marked by axial 

 ribs, which vary greatly in strength in the different species. The spiral 

 sculpture is restricted to the umbilicus. Aperture ovate ; peristome double, 

 the outer very broadly expanded. Operculum with a pseudolamella. 



Type species: Cyclostoma ambigua I^amarck = Salle poma ambiguum 

 (Lamarck). 



KEY TO THE SPECIES OF SALLEPOMA" 



Axial ribs distantly spaced. 



Shell elongate-ovate ambiguum 



Shell elongate-conic corailense 



Axial ribs not distantly spaced. 



Last whorl solute vachense 



Last whorl not solute. 



Suture strongly constricted occidentale 



Suture not strongly constricted pulchellum 



^* Sallepoma mutabile is not included; see information under that species. 



