BULINUS. 259 



Genus BULINUS, Adanson. 



Tentacles filiform, setaceous. Mantle simple-edged, and 

 not reflexed over the shell. 



Shell sinistrorsal, elongated, polished, thin ; spire acumi- 

 nated ; aperture narrow, produced anteriorly ; inner lip 

 simple ; outer lip acute. 



Syn. Nauta, Leach. Aplexa, Fleming. Aplexus, 

 Gray. 



Ex. B. hypnorum, Linnceus, pi. 84, fig. 2. Shell, B. 

 hypuorum, fig. 2, a. 



This genus bears the same relation to Physa that Limncea 

 does to Amphipeplea; it is readily distinguished from 

 Physa by the included mantle, and comprises a group with 

 smooth, translucent, glassy shells, frequenting the fresh- 

 water ponds of Europe and America ; a few species assume 

 a considerable size, as B. Peruvianas from Chili, and B. 

 Mauyerce from California ; one species, B. hypnorum, is 

 common in the weedy dykes of many parts of England. 



Sjiecies of Bulinus. 



abbreviatus, Beck. irapluviatus, Morel. 



Adansonii, Gray. Maugerae, Gray. 



affinis, Eydoux. Peruvianus, Gray. 



elatus, Gould. suturalis, Beck. 



elongatus, Jay. ventricosior, Beck. 



hypnorum, Linn. Wahlbergi, Krauss. 



