THE CYCLOPHORID LAND MOLLUSKS OF AMEiRICA 39 



Genus CROCIDOPOMA Shuttleworth 



1857. Crocidopoma Shtjuleworth, Journ. Conchyl., vol. 5, pp. 271-272. 

 1891. Crocidopoma Crosse, Journ. Conchyl., vol. 39, p. 160. (Type, Crocidopoma 

 floccosum (Shuttleworth).) 



This genus embraces small aperostomid molliisks whose whorls are 

 marked by strong spiral cords and whose operculum bears a strongly 

 elevated and outwardly reflected calcified lamella. The basal 

 chondroid plate extends beyond the turns of the calcified lamella and 

 breaks up on the outside into slender, thin, fluted, and striated 

 fimbriations. 



Type: Cyclostoma {Cyclotus) -floccosum Shuttleworth =6^ro(7^- 

 dopoma {Crocidopoma) floccosum, (Shuttleworth). 



The genus appears to be confined to Cuba and Hispaniola. It breaks 

 up into two subgenera, the typical one of which, Crocidopoma, is con- 

 fined to Hispaniola, while Cyclocuhana is restricted to Cuba. 



KEY TO THE SUBGENERA OF CROCIDOPOMA 



Fimbriations of chondroid plate extending above edge of calcareous 

 lamella Crocidopom.a 



Fimbriations of chondroid plate not extending above edge of cal- 

 careous lamella Cyclocubana 



Cyclocubana, new subgenus 



In this subgenus the fimbriations of the outer edge of the chondroid 

 basal plate extend but little if at all beyond the outer edge of the 

 calcareous lamella. 



Type: Cyclotus perdistinctus GundlsLoh.^ Crocidopoma {Cyclocu- 

 hana) perdistinctum (Gundlach). 



KEY TO THE SPECIES OF THE SUBGENITS CYCLOCUBANA 



Shell planorboid perdistinctum 



Shell depressed-helicoid gundlacM 



CROCIDOPOMA (CYCLOCUBANA) PERDISTINCTUM (Gundlach) 



Shell planorboid, horn colored. Nuclear whorls about 1.5. Post- 

 nuclear whorls very strongly rounded, circular in cross-section with 

 strongly channeled suture, marked by well-raised spiral lirations vary- 

 ing in number in the different subspecies. The axial sculpture con- 

 sists of incremental lines. The last whorl may or may not be solute. 

 Operculum typical of that of the subgenus. 



This species differs from Crocidopoina {Cyclocubana) gundlachi 

 in having the spire very depressed ; in the latter, it is depressed-heli- 

 coid. We are recognizing two subspecies : 



