MELANIA. 



Genus are nearly smooth on the outside, but they are 

 more frequently remarkable for various grooves, gra- 

 nulations, tubercles, and even sharp points; and these 

 are for the most part more strongly marked at the 

 upper part of the volutions, though sometimes extend- 

 ing over the whole. The outside, of the recent species, 

 is also covered with a generally strong, horny, dark 

 brown or black, sometimes olivaceous, brownish or 

 greenish epidermis; and the aperture is closed with an 

 oblong, horny, spiral, not always smooth operculum, of 

 only two or three volutions. The Melanice^ in common 

 with other fresh water shells, are frequently eroded at 

 the most prominent parts, so much so, that the spire is 

 sometimes decollated, and the shell remains of less than 

 half its natural length. 



The Genus to which Melania seems most nearly 

 related, in respect of the characters of the shell, is Tur- 

 ritella; the form of the aperture, which is nearly round 

 in the latter^ and the nature of the epidermis will easily 

 distinguish them when recent : this last mentioned cha- 

 racter is, however, of no avail in the fossil species. 

 Most of the recent Melanice are from the rivers of warm 

 climates. 



The fossil species occur in the fresh water formation, 

 and probably in some others, but they are very abundant 

 in that amhiguous bed, commonly called the " upper 

 marine." Headen Hill, in the Isle of Wight, and Charl- 

 ton, near London, furnish great numbers of a few species. 

 Some other sorts abound in analogous beds in the neigh- 

 bourhood of Paris, and in Normandy. Whether the 

 shells called Melanice, striata, Mineral Conchology, tab. 

 47; Heddingtoniensis, tab. 39, lineata, tab. 218; and some 

 others from secondary strata, should be considered as 

 true MelanicB or not, we do not undertake to decide, the 

 determination of this point involves considerations that 

 are foreign to the object of this work, and too closely 

 connected with the nature of the strata in which they 

 occur, for us to venture to advance any opinion. 



In our plate we have given representations of 



Fig. 1. Melania Amarula. 



2. , a new species ? from the Isle of France ? 



3. mhulata. 



4. - costellata, 



5. ■ ■ I marginataf 



