PULMONATA PLANOBB1DAE PLANOEBIS PABVUS. 



947 



were found in the washed up grass from the bottom ; but, although carefully 

 searched for, no living individuals were secured. 



Mr. Tryon informs me our specimens are unusually large, with the 

 margin of the aperture expanded like those from the Saint Lawrence River, 

 described by Mr. Whiteaves as Planor'bls macrostomus. 



Collected by expedition as follows: 



Subgenns Gyraulus, Agass. 

 PLANOEBIS PABVUS, Say. 



Planorbis parvus, SAY,-Nich. Encycl. 1817-'19, pi. i, f. 6. SAY, Conch., Bintiey's ed., 45, 

 pi. Ixix, f. 6. HALD., Mon., 1844. 27, pi. iv, figs. 19-23. GOULD, Invert., 

 1841, 209, f. 139. ADAMS, Verm. Moll., 1842, 156. DEKAY, N. Y. Moll., 1843, 

 63, pi. iv, f. 58. ANON., Can. Nat,, ii, 1857, 208, f. . BINNEY, Land & Fresh 

 Water Shells N. A., pt. ii, 1865, 133, figs. 222-224. EGBERTS, U. S. Geol. 

 Stirv. Terr., 1870, 468. 



Planorbis concavus, ANTHONY, Shells of Cincinnati (no desc.). 



Planorbis elevatus, ANTHONY, Bost. Jour. Nat. Hist., iii, 1840, 327, pi. iii, f. 16. 

 GOULD, Invert. Mass., 1841, 207. DEKAY, N. Y. Moll., 1843, 65. 



Helix parvus, EATON, Zool. Text-Book, 1826, 115. 



Abundant throughout the United States. 

 Collected as follows : 



