SECTION X. 20! 



upper fide is fine chefiiut brown, fome- 

 what convex, and rifes to a knob or point 

 which is not central, but placed fide- 

 ways. It is this upper fide that re- 

 sembles a Limpet. The under part is 

 quite milk white, flattifli, and round ; the 

 mouth femiclrcular, the inner lip rifes or 

 fwelis, expands or faces quite to the up- 

 per fide, and is tootlied with two flron<T 

 teeth. It is a very curious fpecies, and is 

 ft ill undifcovered recent, or from the fea. 



Helix. My character of this kcond ge- 

 nus is, that they are mofi: generally round 

 mouthed Snails, whofe fpires lie hot izon- 

 tal, or between two levels. PI. 111. fig lo, 

 the Planorbis River Snail. 



The arrangement this genus hears with 

 fyftematifis is among the Snails. Moft of 

 them being land or frcih water Shells, are 

 placed by Lifter among the terreftrial and 

 fluviatil Snails ; and the Do]phiii, a fta 

 Jtind, he has placed, Lib. iv. aaioug the 



