266 PROCEEDINGS OF TH'E NATIONAL MUSEUM Vol.89 



reflected, almost fusing with the outer; the outer very much thickened, 

 broadly expanded and decidedly fluted all around. Operculum with 

 subcentral depressed nucleus and a broad calcareous lamella, which is 

 reflected to parallel the chondroid plate on the last turn, and which 

 forms a continuous surface on the outside. 



This species was described from Monte Toro, Guantanamo, Oriente 

 Province. 



The specimen described and figured is one of two, U.S.N.M. No. 

 356345, received from Poey. It has a little over 4 whorls and meas- 

 ures: Length, 9.7 mm.; greater diameter, 9.8 mm.; lesser diameter, 

 7.5 mm. The other specimen has a little over 4 whorls and measures: 

 Length, 8.1 mm.; greater diameter, 8.7 mm.; lesser diameter, 6.6 mm. 



Gundlach states of this species (Malakozool. Blatter, vol. 6, p. 70, 



1859): "Anunal whitish with white dots above which become fused 



into spots. Head with olive colored suffusion and dark dots, reddish 



within. Feelers cinaabar red with thickened brownish apex. The 



first turn of the animal appears greenish through the substance of 



the shell." 



Aguayotudora, new subgenus 



Shell varying from elongate-ovate to elongate-conic. Nuclear 

 whorls microscopically granulose. Postnuclear whorls marked by 

 axial ribs and by spiral threads, both of which elements vary ma- 

 terially in strength in the different species. The axial ribs may or 

 may not be gathered into tufts or they may or may not form cusps 

 at the summit. There is no siphon or breathing pore. Peristome 

 simple. Operculum typically tudorid. 



Type: Tudora {Aguayotudora) aguayoi, new species. 



KEY TO iTHE SPECIES OF THE SUBGENUS AGUAYOTUDORA 



Axial ribs exceedingly fine suavis 



Axial ribs not exceedingly fine. 



Axial ribs gathered into broad tufts cristata 



Axial ribs not gathered into broad tufts. 



Axial ribs obsolete on last whorl crassiuscula 



Axial ribs not obsolete on last whorl. 



Axial ribs expanding into hollow cusps at the summit. 



Shell elongate-conic bermudezi 



Shell ovate recta 



Axial ribs not expanding into hollow cusps at the 

 summit. 



Axial ribs decidedly scalloped asperata 



Axial ribs not decidedly scalloped. 



Axial ribs tuberculate tuberculata 



Axial ribs not tuberculate. 



Axial ribs very regular aguayoi 



Axial ribs irregular. 



Umbilicus broad varicosa 



Umbilicus narrow obesa 



