88 
by Reeve, sufficiently describe that organ, and from its partiality to 
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 interrogation 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. Patupomus, Swains. 
Animal inhabiting gently-running or still water. Operculum horny, 
subtriangularly ovate, with the apex superior and slightly inclined ; 
concentrically striate ; nucleus subcentral, sinistral. 
. decussatus, Reeve ? 
. Stephanus, Benson? 
conicus, Gray. 
. bifasciatus, Reeve. 
spiralis, Reeve. 
pictus, Reeve? 
bacula, Reeve? 
. abbreviatus, Reeve? 
. clavatus, Reeve? 
. Maurus, Reeve? 
. rudis, Reeve? 
. levis, Layard, 
. palustris, Layard. 
. chilinoides, Reeve. 
. phasianinus, Reeve. 
acutus, Reeve. 
. bicinctus, Reeve. 
constrictus, Reeve. 
nigricans, Reeve. 
. paludinoides, Reeve. 
punctatus, Reeve. 
. globulosus, Reeve? 
yt teh 
htt hh 
Genus 2. Ganea*, 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. olivacea, Reeve? 
Genus 3. Tanai, 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. area, Reeve. T. Reevei, Layard. 
T. Layardi, Reeve. T. similis, Layard. 
T. undata, Reeve. T. violacea, Layard. 
T. funiculata, Reeve. 
Genus 4. Puitoporamis, 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. 
