THE NAUTILUS. 101 



Zouito/des nitida Miilier. Aliundant in low, wet fields. 



Zonitoides arborea Say. Common. 



Euconulus fulvns Miilier. Rare, found four. 



Gastrodonta ligera Say. Abundant, woods. 



Gastrodonta multidentata Binney. Rare. 



Pyramidula alternatu Say. Abundant everywhere. One speci- 

 men is turreted, having a sharp angle at the periphery, and the 

 suture placed far below the angle. 



Pyramidula striatella Anthony. Rare. 



Pyramidula perspectiva Say. Rare, west side of lake. 



Helicodiscus lineatus Say. Rare. 



Polygyra tridentata Say. Common. 



Polygyra sayi Binney. Rare, 8 on 1 sq. yd. No others found. 



Polygyra albolabris Say. Abundant. 



Polygyra albolabris dentota Walker. Rare. 



Polygyra exoleta Binney. Rare. 



Polygyra palUala Say. Common. 



Polygyra thyroides Say. Common. 



Polygyra Mrsuta Say. Rare. 



Polygyra monodon Racket. Rare. 



Polyyyra monodon fraterna Say. Common. 



Vallonia pulchetta Miilier. Common. 



Circinaria concava Say. Rare. 



Piipoides marginata Say. Rare. 



Vertigo ovata Say. Rare. 



Vertigo ventricosa Say. Rare. 



Cochlicopa lubrica Miilier. Abundant. 



Bifidaria corticaria Say. Rare. 



Bifidaria contracta Say. Common. 



Bifidaria armifera Say. Rare. 



Bifidaria pentodon Say. Rare. 



Strobilops labyrinthica Say. Rare. 



Succinea obliqua Say. Abundant. 



Succinea obliqua totteniana Lea. Rare. 



Succinea retusa Lea. Common. 



Succinea avara Say. Common. 



