138 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



the basal plate or it may be obliquely situated or reflected to parallel 

 the basal plate. It may be almost smooth or ribbed. 

 Type genus : Annuhria Schumacher, 



KEY TO THE GENERA OP THE SUBFAMILY ANNULARIINAE OF HISPANIOLA 



Opercular lamella reflected to join that of succeeding turn, thus 

 forming a continuous surface. 



Shell helicoid Petasipoma 



Shell ovate Colobostylus 



Opercular lamella not reflected to join that of succeeding turn, 

 thus not forming a continuous surface. 

 Shell helicoid or depressed-helicoid. 



Spiral sculpture absent Rolleia 



Spiral sculpture not absent. 



Outer peristome of inner lip with a deep sinus Lagopoma 



Outer peristome of inner lip without a deep sinus... Abbottella 

 Shell not helicoid or depressed-helicoid. 



Shell of turbinid outline Eyerdamia 



Shell of not turbinid outline, ovate or elongate-conic. 

 Intercostal spaces marked by microscopic spiral 



lines Weinlandipoma 



Intercostal spaces not marked by microscopic 

 spiral lines. 



Axial ribs fused into tufts at summit Troschelvindex 



Axial ribs not fused into tufts at summit... Christophipoma 



PETASIPOMA, new genus 



Shell helicoid, whorls strongly rounded, marked by both axial ribs 

 and spiral threads. The intersection of the axial ribs and spiral threads 

 form conspicuous, almost sharp nodules. Base broadly, widely um- 

 bilicated, the umbilical wall marked like the spire. Aperture circular; 

 peristome double. Operculum with central nucleus, bearing the strong 

 convex lamella whose outer edge touches and fuses with that of the suc- 

 ceeding turn. On the last whorl, however, the basal chondroid plate pro- 

 jects somewhat beyond the lamella. The lamella is marked by fine, re- 

 tractively slanting hairlines. 



Type species : Petasipoma bombardopolense, new species. 



PETASIPOMA BOMBARDOPOLENSE, new species 



Plate 21, Figures 4-6 



Shell helicoid, wax-colored. Nuclear whorls 2, small, inflated, strongly 

 rounded, forming a rather conspicuous apex. Postnuclear whorls strongly 

 rounded and marked by sublamellar axial ribs, between which a number 

 of finer hairlike threads are present. Of the strong axial ribs, 55 are 

 present on the last turn. The spiral sculpture consists of weak cords 

 that at their junction with the axial ribs render these conspicuously nodu- 

 lose, the nodules being oval with their long axis parallel with the ribs. 

 Of these nodules, four are present on the first turn and seven on the 

 second and the last turn between summit and periphery. On the last 

 whorl the nodules at the summit become intensified. Suture narrowly 



