58 POMATIOPSIS. 



change the name, because in Januaiy, 1840, 

 Mr, John G. Anthony described an Amnicola 

 under the same name, — which of course had 

 priority. Mr. Anthony suggested '^ Say ana " 

 for Dr. Lea's species, and under that name it 

 has been hitherto known. But the species 

 differs generically from Amnicola, and as Dr. 

 Lea's name is thus again capable of being used, 

 I restore it. 



The animal of Pomatiopsis prefers damp loca- 

 tions in the vicinity of streams, but does not, 

 like the Amnicola, live habitually under water. 

 It is an air-breather, but possessed of a true 

 gill. Its locomotion is made by first protruding 

 and attaching the snout, then carrying the 

 front of the body forward, and finally drawing 

 the posterior parts after, — very different from 

 the gliding motion of the Amnicola?. The 

 shell of Pomatiopsis is elongated like that of 

 Bythinella, but differs in the margin of the lip 

 being reflected, presenting a very striking re- 

 semblance to the European terrestrial genus 

 Pomaiias, — whence the generic name. 

 (39) 



