AMNICOLA LIMOSA. 11 



nearly orbicular; labrum with the superior edge 

 not appressed to the preceding whirl, but simply 

 touching it; umbilicus rather large, rounded." 



COLOR corneous, with a bluish tinge. 



GEOGRAPHICAL DISTRIBUTION. Seems to occur 

 from Maine to Pennsylvania and Ohio. "Ex- 

 tremely numerous on the muddy shores of the 

 rivers Delaware and Schuylkill, between high 

 and low water marks." Say. 



OBSERVATIONS. 



" The aperture somewhat resembles that of a 

 Valvata, to which genus it may probably be 

 referrible." Say. It occurs on the Susque- 

 hanna in company with A. decisa. In my cor- 

 respondence I have used the name 'limoscf in 

 accordance with the only definite character 

 given, viz: "length A, breadth iV inch," which 

 does not properly apply, the breadth being equal 

 to the length ; but that I was wrong, I am con- 

 vinced by several considerations, the principle 

 being the comparison instituted by Say between 

 his porata and limosa. A reference to my figures 

 5, 6, and 8, will show how closely these cor- 

 respond. 



