PLANORBIS. 209 



22. PLANORBIS DEFLECTUS, Saij. 



Hald. Monog. p. 25, t. 4, figs. 4—7. 



Inhabits all the Northern and Middle States 

 east of the Rocky Mountains. 



23. PLANORBIS DILATATUS, Gould. 

 Hald. Monog. p. 23, t. 4, fig. 16—18. 



I consider Mr. Lea's PJ. Buchanensis syno- 

 nymous with this species, and not with PI. 

 exacutus, as it is considered by Mr. Binney. 



The species appears, from our imperfect data, 

 princiiDally confined to the Eastern and Mid- 

 dle States, and does not appear to be any- 

 where abundant. Mr. Binney's figure of the 

 base represents a wide umbilicus, and does not 

 in the remotest degree resemble the figure of 

 Gould's from which it is said to be copied. 

 (56) 



