102 PROCEEDINGS OP THE ACADEMY OF 



Lymnaea gracilis, Say. 



Schuyler's Lake. At times very abundant. Usually scarce. 

 Lymnaea humilis, Say. 



Less abundant than desidiosa. 

 Lymnaea pallida, Adams. 



Little lakes. Very scarce. 



Lymnaea stagnalis, Say. 



Traces of this species have been found in the lakes elsewhere 

 named. A single dried specimen (with the soft parts) was found 

 in the Erie Canal, spring of 1871. Probably introduced from 

 Cayuga Lake.? 



Lymnaea umbilicata, Adams. 



None have been seen for many years. All that have been found 

 inhabited a pool of stagnant water in a wood lot that has long 

 since been cleared, and the pool dried up. 



Margaritana marginata, Say. 



Erie Canal and Mohawk River ; not abundant. 

 Margaritana rugosa, Barnes. 



More abundant than the preceding, in the same localities. 



Margaritana undulata, Say. 



Single specimens have been found in the Erie Canal and Mo- 

 hawk River. The species abounds in streams emptying into 

 Schuyler's Lake. 



Melantho decisus, Say. 



Inhabits Schuyler's Lake and Little Lakes without any asso- 

 ciate species. Found also in the Erie Canal and Mohawk River 

 with the two species next named. A few reversed specimens have 

 been found. 



Melantho integer, Say. 



The opercle of the adult has the form of that of 31. ponderosus 

 Say. I am inclined to regard these shells as varieties of jjonde, 

 rosus. Reversed and malformed specimens occur sometimes in 

 considerable numbers in the Erie Canal. Largest shell found is 

 over two inches long. 



Melantho rufus, Haldenian. 



This species, as well as integer, has evidently been introduced 



[July 16, 



