GASTEEOPODA. 247 



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



Sub-genera. Melandtria, 'Bo^?}■^iich.. M. fluminea.* PI. YIII., 

 Pig. 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 Woolwich 

 sands. Old World, India, Philippines. 



Vibex, Oken, V. fuscatus, PL YIII., Pig. 29. Y. auritus. 

 West Africa. Whorls spirally ridged, or muricated; aperture 

 broadly channeled in front. 



Ceriphasia, Sw., C. sulcata. North America. Aperture like 

 vibex ; slightly notched near the suture. 



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

 channeled in front. 



Melafusus, Sw, (lo, Lea. Glottella, Gray.) M. fluviatilis. 

 PL YIII,, Pig. 27. United States. Aperture produced 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 YIII., Pig. 28. 



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

 States. 



Amnicola, G. and H. A. isogona. PL IX., Pig. 23. United 

 States ; inhabits the fresh waters of New England, gregarious 

 on stones and submerged plants. 



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

 thickened externally, all round. 



Glea, Bens. C. annesleyi. South India. 



Paltidomtjs, Swainson. 



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



Synonyms, Tanalia, Gray. Hemimitra, Sw. 



Type, P. aculeatus, Gm. species. PL IX., Pig. 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 others), 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 like a pirena in the form of its aperture. 



