16 



AMNICOLA LUSTRICA, Say. 



SYNONYMS AND REFERENCES. 



PALUDINA LUSTRICA, SAY. Journ. Acad. Nat. Sci., vol. 

 ii. p. 175. 



DESCRIPTION. 



SHELL "conic; whorls slightly wrinkled, con- 

 vex; suture profoundly indented; aperture oval, 

 nearly orbicular; labrum with the superior edge 

 not appressed to the preceding whirl, but simply 

 touching it; umbilicus rather large, rounded. 



"Length less than T V inch. 



"Cabinet of the Academy." 



"The smallest species I have seen.* The 

 aperture somewhat resembles that of a Valvata, 

 to which genus it may probably be referrible. 

 Mr. Jessup obtained two specimens on the 

 shores of Cayuga lake." Say. 



* But one of the two specimens referred to by Say is 

 perfect, and may be seen in the Cabinet of the Academy of 

 Natural Sciences, Philadelphia. It is a slender pale yel- 

 lowish-brown shell, having four volutions, and is 5 or 6 

 millimetres long. It is closely allied to A. lapidaria, of 

 which it may possibly be the young. 



