110 IIELICELLINiE. 



Hartmanni, Pfeiff. raclula, PJeiff. 



Metcalfi, PJeiff. rotatoria, V. d. Busch. 



Osbeckii, Phil. strigilis, Pfeiff. 



Papua, Less. Swainsoni, Pfeiff. 



plauorbis, Less. 



Sub-gen. conulus, Fitzinger (Petasia, Beck. Trochiscus, Held., 

 uot Sow. Perforatella, Schlut.). 



Shell thin, perforate, turbinately globose, arctispiral ; aperture 

 obliquely lunar ; peristome internally labiate, patulous or subre- 

 flexed, rarely simple, basal margin often dentate. 



bidens, Chem. fusca, Mont. 



calculosa, Gould. Gundlachi, Pfeiff. 



Cobresiana, Alten. leucozona, Ziegl. 



edentula, Drap. ligera, Say. 



Egena, Say. stenotrema, Ferus. 



fulva, Drap. subtilissima, Gould. 



Genus DISCUS, Fitzinger. 



Shell widely unibilicated, depressed, discoid or turbinate, 

 rugose or costulately striate ; whorls equal or gradually 

 increasing ; aperture lunately rotund ; peristome simple, 

 straight, acute. 



Syn. Patula, Held. Euryomphala, Beck. Pyramidula, 

 Fitz. Gonyodiscus, Fits. Acanthinula, Beck. Phlebecula, 

 Lowe. Lucilla, Lowe. 



Ex. D. rotundatus, Midler, pi. 71, fig. 7. Shell, D. 

 rotundatus, fig. 7, a. 



This genus is chiefly confined to temperate regions ; the 

 species are inhabitants of the whole of Europe and North 

 America ; a few are from Central America, Brazil, Bolivia, 



