224 PNEUMONOBRANCHIATA. 



Inhab. on moss and Jungermannise, in damp places, 

 springs, &c. 



Shell the tenth of an inch long, of a cylindri- 

 cal form, and hardly decreasing in diameter for its 

 whole length, highly polished and marked with rather 

 remote regular longitudinal striae, which are hardly 

 distinguishable without a good glass ; spire composed 

 of six very slightly raised but well-defined volutions, 

 the two terminal ones of which are smaller and paler ; 

 aperture roundish-oval, with the margin thin, and a 

 little reflected at the pillar, where it forms a slight 

 perforation. 



The animal and shell are sometimes dark brown 

 and at others pale yellowish white. They are some- 

 times found reversed. 



3. Conovulus. (Conovulus.) 



Shell oval, obconic, last whorl long, compressed; mouth 

 linear ; pillar with two or three spiral plaits ; outer 

 lip simple, or very slightly reflexed ; throat grooved. 



The foot of the animal is obovate, oblong, blunt 

 in front and behind; tentacles contractile, filiform, 

 slightly ringed ; eyes at their inner base ; muzzle 

 porrect, notched in front, as in Limnceus ; mantle 

 closed all round, with the exception of a perforation 

 at the point of junction of the outer and inner lip. 

 The pillar of the shell is plaited in all ages. 



The animal, in habit, manner, and appearance, very 

 greatly resembles that ofAplexa or Limnceus, but dif- 

 fers in the tentacles being filiform and ringed. 



They live in brackish water, and salt-water marshes, 

 at the roots of rushes, and are sometimes found under 

 stones on the sea-shore near the mouth of rivers. 



