CYCLOSTOMUS. 



291 



]ridoj)/tora is an African group, being found in Zanzibar, 

 Natal, Madagascar, Seychelles, and the Isle of France; 

 Lithidion is a peculiar group from Arabia, Socotara, and 

 Madagascar ; the sub-genus Otopoma is also from Arabia, 

 Socotara, Yemen, Mogadoxa, the Mauritius, and Madagas- 

 car; while of Leonia, in which the operculum is convex 

 and composed of but one whorl, a single species only is 

 known, from Spain and Algeria. 



Species of Cyclostomus. 



albus, Pfeiff. 

 aplustris, Sow. 

 asper, Pot. and Mich. 

 Banksianus, Sow. 

 Bronnii, C. B. Adams. 

 Caroliuensis, Pfeiff. 

 Chevalieri, C. B. Adams. 

 citrinus, Sow. 

 concinnus, Sow. 

 costulatus, Ziegl. 

 dissectus, Sow. 

 Dominiceusis, Pfeiff. 

 elegans, Mull. 

 euckilus, Pfeiff. 

 fascicularis, Pfeiff. 

 fimbriatus, Lam. 

 fulvescens, Sow. 

 glaucus, Sow. 

 Goudotianus, Soiv. 

 gratus, Petit. 

 griseus, Pfeiff. 

 Humphreysianus, Pfeiff. 

 iusularis, Pfeiff. 

 Jayauus, C. B. Adams. 

 lamellosus, C. B. Adams. 

 laevigatas, Webb and Berth. 

 ligatus, Mull. 



ligulatus, Gratel. 

 liueatus, Pfeiff. 

 multifasciatus, Gratel. 

 Novae Hiberniae, Quoy. 

 obsoletus, Lam. 

 pyrostoma, Sow. 

 Rangeliuus, Poey. 

 reticulatus, Adams and Reeve. 

 retrorsus, 0. B. Adams. 

 rugulosus, 0. B. Adams. 

 saccatus, Pfeiff. 

 salebrosus, Morel. 

 Sowerbyi, Pfeiff. 

 striatulus, Pfeiff. 

 subliratus, Pfeiff. 

 sulcatus, Drap. 

 sulculosus, Ferus. 

 tectilabris, 0. B. Adams. 

 tenuis, Sow. 

 tersus, Bens. 

 thysanoraphe, Sow. 

 virgatus, Sow. 

 Wilkinsonii, 0. B. Adams. 

 xanthochilus, Sow. 

 Yallahensis, C. B. Adams. 

 Zanguebaricus, Petit. 

 zouatus, Petit. 



