7© Natural History Buli>etin. 



Genus Bulinus — Adan. 



B. HYPNORUM. Z. 



Locally very common in the northern half of the state in 

 ponds and sluggish streams. We have specimens from Frank- 

 lin county (collected by Mr. J. W. Preston), which are curi- 

 ously spirally banded with white. 



^^ UB-FAMIL 1 - -PLANORBlNyE. 



Genus Planorbis — Guett. 



Sub-^enus Planorhclla — Hald. 



P. CAMPANULATUS— KS"<:/jy. 



Quite common, especially in the ponds and lakes of the 

 northern portion of the state. 



Sub-genus Helisoma. — Sivains. 



P. TRivoLVis. — Say, 



Exceedingly common. A depressed, wrinkled form is com- 

 monly sent out as P. glabratus — an entirely distinct south- 

 ern species. Two distinct forms occur. One much larger, is 

 found in the lakes and ponds of the northern part of the state 

 and is probably a distinct species. 

 P. BICARINATUS. — Say. 



This clearl}^ marked species is common in sluggish waters. 



t^ub-genus Menctus— H.& A. Ad. 

 P. EXACUTUS. — Say. 



Common in ponds, on sticks, etc. 



Sub-genus Gyraulus. — Ag. 



P. DEFLECTUS. — Say. 



Occurs sparingly in the northern and eastern portions of the 

 state. 



P. DILATATUS. Gld. 



This small Planorbis with dilated aperture is probably more 

 common than is now supposed. It is undoubtedly often mis- 



