134 Zoological Society :— 



sluggish waters (two species being found in the marshy borders of 

 tanks or artificial lakes), it better suits the name than any of the 

 other divisions. A note of intei-rogation after a species implies that 

 I have not seen the operculum, but from the form I consider it to 

 belong to the division in which it is placed. 



Genus 1. Paludomus, Swains. 



Animal inhabiting gently-running or still water. Operculum homy, 

 subtriangularly ovate, with the apex superior and slightly inclined ; 

 concentrically striate ; nucleus subcentral, sinistral. 



P. Icevis, Layard. P. decussatus, Reeve? 



P. palustris, Layard. P. Stephanus, Benson? 



P. chilinoides, Reeve. P. conicus, Gray. 



P. phasianinus, Reeve. P. bifasciatus. Reeve. 



P. acutus, Reeve. P. sjnralis, Reeve. 



P. bicinctus, Reeve. P. pictus, Reeve ? 



P. constrictus. Reeve. P. bacida, Reeve 1 



P. nigricans. Reeve. P. abbreviatus, Reeve? 



P. paludinoides, Reeve. P. elavatus. Reeve ? 



P. punctutus, Reeve. P. Maurus, Reeve 1 



P. globulosus, Reeve? P. rndis. Reeve? 



Genus 2. Ganga *, Layard. 



Animal inhabiting gently-running water. Operculum horny, sub- 

 triangularly ovate ; apex superior, slightly inclined, concentrically 

 striate ; nucleus subcentral, dextral. 



G. dilatata, Reeve. G. neritoides. Reeve ? G. oUvacea, Reeve ? 



Genus 3. Tan alia. Gray. 



Animal fluviatile, delighting in the most rapid mountain torrents. 

 Operculum horny, subtriangularly ovate ; apex lateral, lamellated ; 

 nucleus lateral, dextral. 



T. loricata. Reeve. T. Gardneri, Reeve. 



T. crinascens, Reeve. T. Tennentii, Reeve. 



T. (erea, Reeve. T. Reevei, Layard. 



T. Layardi, Reeve. T. similis, Layard. 



T. vndata. Reeve. T. violacea, Layard. 

 T. funiciUata, Reeve. 



Genus 4. Philopotamis, Layard. 



Animal fluviatile, amphibious, delighting in rocky torrents. Oper- 

 culum horny, subtriangularly ovate ; apex superior, paucispiral ; nu- 

 cleus sub-basal, dextral. 



Ph. sulcatus, Reeve. Ph. Thwaitesii, Lay. Ph. regalis. Lay. 

 * Cingalese name for a river. 



