OF NORTH AMERICA. 163 



DISTRIBUTION : North and middle America. Principally south 

 of Canada and east of the great plains. 1 



The Succinea-like shells of Lymncea columella have been usually 

 placed in Radix on account of the large, somewhat flaring aperture. 

 Dr. Dall, in hi's Alaska Mollusca, has expressed the opinion that it 

 belongs to Stagnicola. A study of the anatomy shows that it differs 

 markedly from Stagnicola in its genitalia and in its radula. The pe- 

 culiar shape and small size of the prostate, the number and position 

 of the retractor muscles of the male organ and the Succinea-like form 

 of the shell have led the author to erect a new genus for the reception 

 of these peculiar shells. 



Pseudosuccinea columella (Say). Plate XXIII, figures 8-20; 

 plate XXIV, figures 1-4. 



Lymnaa columella SAY, Journ. Phil. Acad., I, p. 14, 1817. EARLE, Report 

 on Geol. Zool. Mass., p. 558, 1833. GOULD, Lamarck's Genera, p. 69, 1833. 

 RAVENEL, Cat. Sh. Cab. Ravenel, p. 11, 1834. EARLE/Geol. Zool. Mass., p. 23, 

 1835. HITCH., Geol. Zool. Mass., p. 27, 1835. GOULD, Rep. Geol. State Maine, 

 I, p. 119, 1837. LEA, Trans. Amer. Phil. Soc., IX, pp. 11, 12, 1841. LIN SLEY, 

 Amer. Journ. Sci., XLVIII, p. 282, 1845. WHEATLEY, Cat. U. S. Shells, p. 23, 

 1845. LEA, Obs., IV, pp. 11, 12, 1848. JAY, Cat. 4th ed., p. 268, 1852. LEWIS, 

 Proc. Phil. Acad., 1856, p. 259. SAY, BINNEY, Reprint, pp. 56, 60, 1858. MORSE, 

 Amer. Nat., Ill, p. 651, pi. 11, fig. 17, 1870. LEWIS, Proc. Phil. Acad., 1872, p. 

 109 ; Proc. Phil. Acad., 1872, p. 101. SCUDDER, Bull. Nat. Mus., 23, p. 200, 1885. 

 RHOADS, Nautilus, XVIII, p. 66, 1904. DALL, Land & F.-W. Sh., p. 70, fig. 47, 

 1905. PILSBRY & FERRISS, Proc. Phil. Acad., 1906, p. 161. BAKER, Bull. 111. 

 State Lab. N. H., VII, p. 103, 1906. HINKLEY, Nautilus, XV, p. 40, 1906. 

 PILSBRY & FERRISS, Proc. Phil. Acad., p. 564, 1906. SMITH, Nautilus, XX, p. 91, 

 1907. STERKI, Proc. Ohio State Acad. Sci., IV, p. 382, 1907. HENDERSON, 

 Nautilus, XiXI, p. 7, 1907. JACKSON, Nautilus, XXI, p. 143, 1908. BAKER, 

 Science, n. s., XXVII, p. 943, 1908. LERMOND, Shells of Maine, p. 37, 1908. 

 COLTON, Proc. Phil. Acad., 1908, pp. 413, 422, 446. BAKER, Nautilus, XXIV, 



p. 69, 1910. Jbo* ^JL*j \ <X ' 



Lymnca columella GIRARD, Proc. Nat. Inst., I, p. 81, 1856. CURRIER, Sh. 

 Grand River, Mich., 1859. LEWIS, Proc. Phil. Acad., 1860, p. 18. COUPER, 

 Cat, p. 4. 



Limnaus columella GIBBES, App. Geol. Car., p. XX, 1848. KUSTER, Conch. 

 Cab., p. 44, taf. 8, figs. 3-5, 1862. 



Lymnceus columellus SAY, Journ. Phil. Acad., II, p. 167, 1821. SAGER, 

 Geol. Surv. Mich., p. 15, 1839. SAY, BINNEY, Reprint, p. 65, 1858. 



Limn&a columella SAY, Nich. Encye., IV, p. 56, 1819 (reprint). BECK, 

 Index, p. 113, 1837. POTIEZ & MICHAUD, Galerie, I, p. 216, pi. 22, figs. 15-16, 

 1838. TAYLOR & SHIVERICK, Cat., 1840. GOULD, Invert. Mass., p. 215, fig. 144, 

 1841. PRESCOTT, Sh. Mass., No. 191, 1842. READ, Cat., 1845. RUSSELL, Journ. 

 Essex Co., Nat. Hist. Soc., p. 130, 1852. CHICKERING, List Sh. Portland, Me., 



^Until the anatomy of the European and other exotic species is known 

 it is impossible to assign any of them to this group, although several species 

 have similar shells. 



