'CUBAN ANNULARiroAE — TORRE AND BAHTSCH 193 



are very broad and they are marked by numerous microscopic axial 

 threads. Suture strongly constricted. Periphery inflated, well 

 rounded. Base short, openly mnbilicated, mflated, strongly rounded, 

 and marked by the continuation of the axial ribs and within the umbili- 

 cus and its outer edge by low spiral tlu-eads, which render the axial 

 ribs nodulose. Aperture broadly oval; peristome double, the mner 

 slightly exserted and reflected, but not adnate to the outer; the outer 

 broadly, flaringly expanded, marked by numerous concentric lamellae, 

 broadest on the inner lip, where it is partly reflected over the umbilicus, 

 and at the posterior angle of the aperture. Operculmn typically 

 opisthosiphonid. Siphon at the posterior angle of the aperture 

 reflected backward into the suture. 



The specmien figured, U.S.N.M. No. 425684, is one of 3 paratypes 

 received from Dr. Welch, collected by him on the south slope of Loma 

 de Florencia, Camagiiey. It has 4.5 whorls remaining and measures: 

 Length, 12.0 mm.; greater diameter, 7.0 mm.; lesser diameter, 6.1 mm. 

 The extremely distant spacing of the ribs combined with the notch in 

 the inner lip wiU easily distinguish this from the other Bermudez- 

 siphonas. 



Subgenus Opisthosiphona Henderson and Bartsch 



1920. Opisthosiphona Henderson and Bautsch, Proc. U. S. Nat. Mus., vol. 58, 

 p. 67. 



Opisthosiphons without spiral sculpture on spire and base, the 

 spiral threads being present in the umbflicus only, and with the axial 

 ribs terminating individually without fusing at the summit. There 

 are no microscopic axial lines between the axial ribs. 



Type: Opisthosiphon (Opisthosiphona) moreletianum (Petit). 



KEY TO THE SPECIES OF THE SUBGENUS OPISTHOSIPHONA 



Umbilicus closed pupoides 



Umbilicus open. 



Last whorl decidedly solute moreletianum 



Last whorl slightly solute plicatum 



Last whorl not solute turiguanoense 



OPISTHOSIPHON (OPISTHOSIPHONA) PUPOIDES (Morelet) 



Shell elongate-conic, varying from flesh colored to pale brown, 

 marked by interrupted spiral bands of brown, the elements composing 

 these bands being arranged in both axial and spiral series. Nuclear 

 whorls 2, inflated, well rounded, microscopically granulose. Post- 

 nuclear whorls inflated, strongly rounded, marked by retractively 

 slanting axial riblets, which extend very prominently to the summit, 

 where they become expanded into hollow cusps, usually weaker ones 

 alternating with stronger ones. Suture strongly constricted, crenu- 

 lated by the denticles at the smimiit. Periphery inflated, well rounded. 



