292 CYCLOSTOMIM. 



Sub-gen. tropidophora, Troschel. 



Shell depressed or elevately turbinated, generally acutely 

 keeled, or strongly striated ; peristome simple, sub-continuous, 

 reflexed, often partially covering the axis. 



Abeillei, Gratel. Kraussianus, Pfeiff. 



articulatus, Gray. liratus, Pfeiff. 



Barclayanus, Pfeiff. Madagascariensis, Gray. 



bicariuatus, Sow. Michaudi, Gratel. 



calcareus, Sow. modestus, Petit. 



campanulatus, Pfeiff. Moulinsii, Sow. 



carinatus, Bom. pulchellus, Sow. 



cariniferus, Sow. pulcher, Gray. 



castaneus, Pfeiff. rugosus, Lam. 



Creplini, Dkr. tricarinatus, Mull. 



Cuvierianus, Petit. trochlea, Bens. 



deliciosus, Ferus. unicarinatus, Lam. 



Deshayesianus, Petit. unicolor, Pfeiff. 



formosus, Sow. vittatus, Sow. 



fusculus, Pfeiff. zonulatus, Sow. 



Sub-gen. lithidion, Gray. 



Operculum sub-orbicular, with a strong, convex, sub-central 

 keel and simple edge. 



Shell depressed, widely umbilicated ; aperture circular; pe- 

 ristome simple. 



depressus, Sow. Souleytianus, Pfeiff. 



desciscens, Pfeiff. sulcatus, Gray. 



niveus, Petit. 



Sub-gen. otopoma, Gray. 



Shell conico-globose or depressed, solid, umbilicated; aper- 

 ture sub-oval ; peristome straight or sub-reflexed, columellar 

 margin generally dilated, more or less covering the umbilicus. 



albicans, Soiv. auricularis, Gray. 



