PLANORBIS. 209 
22. PLANORBIS DEFLECTUS, Say. 
Hald. Monog. p. 25, t. 4, figs. 4—7. 
Inhabits all the Northern and Middle States 
east of the Rocky Mountains. 
28. PLANORBIS DILATATUS, Gould. 
Hald. Monog. p. 23, t. 4, fig. 16—18. 
I consider Mr. Lea’s Pl. Buchanensis syno- 
nymous with this species, and not with Pl. 
exacutus, as it is considered by Mr. Binney, 
The species appears, from our imperfect data, 
principally confined to the Hastern 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) 
