GASTEEOPODA. 247 



Fossil, 25 species. Wealden — . Europe (v. chemnitzia). 



Sub-genera. Tlfe^ana^rm, Bowdich.. M. fluminea.* PL YIII., 

 Fig. 26. Aperture somewliat produced in front ; operculum 

 with rather numerous whorls. This section includes some of 

 the largest species of the genus, and is well typified by the 

 fossil, M. Sowerhii (cerit. melanoides, Sby.), of the Wool^vich 

 sands. Old World, India, Philippines. 



Vihex, Oken, V. fuscatus, PI. VIII., Fig. 29. V. auritus. 

 West Afi'ica. Whorls spirally ridged, or muricated; aperture 

 broadly channeled in front. 



Ceriphasia, Sw., C. sulcata. North America. Apertui-e Hke 

 vibex ; slightly notched near the suture. 



HemisinuSy Sw., H. lineolatus. West Indies. Aperture 

 channeled in front. 



Mekifusus, Sw, (lo, Lea. Griottella, Gray.) M. fluviatilis. 

 PI. VIII,, Fig. 27. United States. Aperture j^roduced into a 

 spout in front. 



Meldtoma, Anthony (not Sw.) M. altilis. 



Shell like anculotus ; with a deep slit at the suture. United 

 States. 



Anculotus, Say. A. prsemorsus. PL VIII., Fig. 28. 



Shell globular ; spire very short ; outer lip produced. United 

 States. 



Amnicola, Gr. and H. A. isogona. PL IX., Fig. 23. United 

 States ; inhabits the fresh waters of Xew England, gregarious 

 on stones and submerged plants. 



Chilostoma, Desh. M. marginala, Eocene. Paris. Peristome 

 thickened externally, all round. 



Clea, Bens. C. annesleyi. South India. 



Pajlttdomtis, Swainson. 



Etymology, palus, a marsh, and domus, home. 



Synonyms, Tanalia, Gray. Hemimitra, Sw. 



Type, P. aculeatus, Gm. species. PL IX., Fig. 34. 



Shell turbinated, smooth, or coronated ; outer lip crenulated ; 

 olivaceous with dark brown spiral lines. 



Distribution, 25 species. Ceylon (Himalaya ?) in the moun- 

 tain-streams, sometimes at an elevation of 6,000 feet. The 

 Himalayan species [melania conica, Gray, hemimitra retusa, Sw., 

 and several othei's), referred to this genus, have a concentric 

 operculum, like paludina. 



* This is a good section of melania, but Mr. Gray's type does not well represent it, 

 being more lilte apirena in tlie form of its aperture. 



