THE CYCLOPHO'RiID LAHSTD MOLLUSKS OF AM]E!RICiA 71 



CYCLOPILSBRYA, new genus 



Medium-sized aperostomine mollusks having a strongly elevated 

 spiral lamella on the outside of the whorls of the operculum, which 

 is concavely curved on the inside. 



Type: Cyclmtoina juf/o-mm C. B. Adiims= Ci/clopilsbrya {Cyclo- 

 jfUshrya) jugosa (C. B. Adams). 



The anatomy of C. (C.) caiihaea (Clench and Aguayo) shows the 

 radula formula 3:3:3:3. 



The genus presents two primary modifications, which may be 

 defined as subgenera, as follows. 



KEY TO THE SUBGENERA OF GENUS CYCLOPILSBRYA 



Lamella curving uniformly inward to a sharp edge Cyclopilsbrya 



Lamella not curving uniformly inward to a sharp edge, but with a 

 broadly expanded fold, which extends from the outside of the free 

 edge outward and downward almost to meet the next turn__- Cyclocaymania 



CYCLOPILSBRYA, new subgenus 



In this subgenus the strongly raised spiral lamella is curved inward 

 and its free outer margin is sharp. 



Type: Oyclostoma jugosum C. B. AdaLms= Cyclopilsbrya {Oydo- 

 pilshrya) jugosa (C. B. Adams). 



This subgenus is confined to western Jamaica, where it ranges 

 through the parishes of Hanover, St. James, Westmoreland, and St. 

 Elizabeth. 



KEY TO THE SPECIES OF SUBGENUS CYCLOPILSBRYA* 



Umbilical keel well developed. 



Wrinkled sculpture of base strong. 



Shell large, greater diameter more than 20 mm westmorelandensis 



Shell small, greater diameter less than 15 mm hendersoni 



Wrinkled sculpture of base feeble. 



Pits outside of umbilical keel profound glenbumiensis 



Pits outside of umbilical keel not profound rupisfontis 



Umbilical keel obsolete. 

 Umbilicus very broad. 



Retractively slanting axial ribs of base very regular striosa 



Retractively slanting axial ribs of base very irregular jugosa 



Umbilicus not very broad. 



Shell large, greater diameter more than 24 mm — caribaea 



Shell small, greater diameter less than 18 mm. 



Sculpture coarsely wrinkled rufilabris 



Sculpture not coarsely wrinkled asperula 



3 1 have not seen C. (C.) besicicki (Chitty) and therefore have not included it in this key. 



