PALUDINA. 



The animals of this genus are of sluggish 

 habits; they feed upon living or decayed vege- 

 table matter, and respire water, in which they 

 live entirely, generally preferring a bottom of 

 soft mud, upon which they are well adapted for 

 progression, on account of the great extent and 

 flexibility of the foot. Its extension in front 

 prevents them from taking food, except when 

 at rest. They prefer nearly stagnant waters, 

 or rivers with sluooish currents. The Paludinae 

 are viviparous, depositing the young in the 

 spring, which have lain in the ovaries during 

 the winter. The sexes are said to be distinct. 

 The genus is here restricted by the omission 

 of the small oviparous species,* with subspiral 

 opercles,. and the foot short anteriorly. 



The shells of some species make so near an 

 approach to those of certain Ampullariae, that 

 it is difficult to distinguish them. In this case, 

 an aperture narrowed posteriorly, and a length- 

 ened spire, will generally indicate the genus 

 Paludina sufficiently for ordinary purposes. 



* As P. lustrica, Say, which is the type of a new genus, 

 (Amnicola, Gould and Hal.) suggested by Dr. Gould. 



