LIMN^A. 101 



with a strong columellar nearly or quite cover- 

 ing the umbilicus. Light horn-color, thin. 



Length 19, diam. 9 mill. 



Greenland. 



The volutions are a little more oblique and 

 the shell is smaller, but otherwise it does not 

 essentially differ from L. palustris. 



17. LIMN^A HOLBOLLII, Mcelkr. 

 Plate 17, fig. 11. 



Shell thin, conic-ovate, spire elongated,, 

 whorls j&ve, well rounded, with deeply im- 

 pressed sutures; aperture small, rounded 

 ovate, columella slightly folded ; umbilicate. 



Length 12, diam. 6 mill. 



Greenland. 



This shell is at once distinguished from the 

 preceding species by its smaller size, rounded 

 whorls and aperture, and open umbilicus. It 

 is allied to L. humilis, Say, but the spire is 

 more elevated and the whorls not so convex ; 

 it is also a more solid species. 



(75) 



