340 



VIVIPARID^. 



or festooned, as in Melania, and the operculum is com- 

 posed of concentric elements arranged around a subcen- 

 tral nucleus. The species, for the most part, come from 

 India and Ceylon. 



Species of Paludomus. 



abbreviatus, Reeve. 

 acutus, Reeve. 

 bacula, Reeve. 

 biciiictus, Reeve. 

 bifasciatus, Reeve. 

 cbilinoides, Reeve. 

 clavatus, Reeve. 

 conicus, Gray. 

 constrictus, Reeve. 

 decussatus, Reeve. 

 globulosus, Gray. 

 Gruneri, Jonas. 

 maurus, Reeve. 



modicella, Lea. 

 nigricans, Reeve. 

 . olivaceus, Reeve. 

 ovatus, Gray. 

 paludinoitles, Reeve. 

 phasiaiiinus, Reeve. 

 puuctatus, Reeve. 

 sanschauricus, Gmel. 

 spiralis, Reeve. 

 spurcus, Eyd. and Soul. 

 Stephanas, Reeve. 

 Zeylanicus, Reeve. 



Genus TAN ALIA, Gray. 



Operculum lamellar, with the nucleus near the front of 

 the outer edge. 



Shell turbinate, solid, imperforate, whorls transversely 

 striated, mvuicated, or grooved, covered with a black, 

 horny epidermis ; spire short, obtuse ; aperture semiovate; 

 inner lip usually flattened; outer lip with the mai'gin 

 crenulated. 



Ex. T. aculeata, CJiemnitz, pi. 36, fig. 3. Operculum, 

 T. Gardneri, Reeve, fig. 3, a, S, b. 



The operculum in this genus is remarkable for the 

 lateral arrangement of the elements, and the marginal 



