forms appear to be quite different; but in a bog, in 

 Stone Creek valley, they were found together, and 

 with intermediate specimens, so that the present 

 form seems to he a var. of ventrieosa. Seen from 

 New York, Michigan, Ohio, and West to Montana, 

 while the type is known in the East, also to Mich- 

 igan and Ohio, and southward in the Alleghanies, 

 to North Carolina. 



55. Vertigo ovata Say. Moist and wet places, not 



very common. 



56. CiONELLA (Ferussacia) lubrica Mueller. Not 



common, in woods. — Westerlund (Fauna III, p. 148) 

 says: "M. Bourguignat, and some with him, con- 

 sider this species the Helix subcylindrica of Lin- 

 naeus. This is at least very doubtful; for L. says 

 of his snail that it is living in fresh water, and is 

 " pallida, anfr. 4, apice obtusissimo, rotundato, aper- 

 tura ovali, margine exteriori reflexo" — characters 

 which are not applicable to our species. It is bet- 

 ter, consequently, to use Mueller's name. 



57. SucciNEA ovALis Gld. Common, variable. 



58. SucciNEA ?. Rare. 



59. SucciNEA AVARA Say. Common; variable in size 



and color of the shell. 



60. Carychium exiguum Say. Common. 



a. (var.?) exile Ad. Common; more in dry, 



elevated situations. The internal lamella, on the 

 columella is formed quite differently from that in 

 the type. 



61. LiMNAEA columella Sav. Not common. 



62. LiMNAEA PALUSTRis Muell. (elodes Say). Common 



in some places. Most specimens have a strong^ 

 rose colored lip when mature. Specimens hatched 

 in August, in a small aquarium, were fully grown 

 in midwinter. 



63. LiMNAEA DESiDiosA Say. Rather common, variable, 

 a. var. or f., , small, scalaroid; very rare. 



64. LiMNAEA HUMiLis Say. Common. 



65. LiMNAEA UMBiLiCATA Ad. ? (var.) Very rare. 



66. Planorbis trivolvis Say. Common. 



