236 THE CHICAGO ACADEMY OF SCIENCES. 



Subgenus SIMPSONIA Nov. Subgen. 



TYPE: Limncea humilis Say. 



SHELL : Similar in general form to that of Galba. 



RADULA: With tricuspid lateral teeth. 



GENITALIA: Similar to Galba. 



This group of small Lymnseas is separated from the subgenus 

 Galba mainly on account of the radula, which has tricuspid instead of 

 bicuspid laterals. The shell offers no definite characters of group value 

 by which to separate Simpsonia from Galba. The subgenus contains 

 the humilis-obrussa-parva group of Lymnaeas, in which the shell is 

 usually small and without marked spiral sculpture. It is mainly con- 

 fined to the northern part of the United States and Canada. 



Galba umbilicata (C. B. Adams). Plate XXX, figures 1-7. 



Limncea umbilicata, C. B ADAMS, Amer. Journ. Sci., i, XXXIX, p. 374, 

 1840. Boat. Journ. Nat. Hist., Ill, p. 325, pi. iii, fig. 14, 1840. TAYLOR and 

 SHIVERICK, Cat., 1840. GOULD, Invert. Mass., p. 218, fig. 149, 1841. PRESCOTT, 

 Cat. Sh. Mass., No. 198, 1842. REED, Cat., 1845. RUSSELL, Journ. Essex Co. 

 Nat. Hist. Soc., p. 130, 1852. LEWIS, Proc. Bos. Soc. N. H., VI, p. 2, 1856 

 (part). TUFTS, Proc. Essex Institute, I, p. 30, 1856. TRUE, Proc. Essex Inst., 



II, p. 195, 1857. WHITEAVES, Can. Nat., VIII, p. 103, 1863. BINNEY, L. & F. W. 

 Sh. N. Am., II, p. 57, fig. 88, 1865. GOULD, BINNEY Ed., Inv. Mass., p. 480, 

 fig. 731, 1870. JEFFREYS, Ann. Mag. N. H., ser. IV, X, p. 247, 1872 (part) ; 

 Journ. Conch., I, p. 8, 1874 (part). H. F. CARPENTER, Random Notes, III, p. 86, 

 1886. PILSBRY, Proc. Phil. Acad., p. 320, 1891. 



Lymn&a umbilicata LEA, Journ. Phil. Acad., VI, pp. 161, 162, 1866; Obs., 

 XI, pp. 117, 118, 1867. SCUDDER, Bull. Nat. Mus., 23, p. 201, 1885. WALKER, 

 Nautilus, XXII, pp. 7, 8, figure 1, pi. 2, figs. 1, 2, 1908; Ottawa Nat., XXII, pp. 

 90-91, fig. 3, 1908. LERMOND, Shells of Maine, p. 37, 1909. BAKER, Nautilus, 

 XXIII, p. 80, 1909. 



Lymncea caperata var. umbilicata JAY, Cat. Ed. 4, p. 268, 1852. 



Limnea umbilicata HALD., Mon. Limn., p. 34, pi. 11, fig. 9, 1842. 



Limneus umbilicatus CLESSIN, Mai. Blatt., n. s., Ill, p. 83, 1881. 



Limncea umbilicata JACKSON, Nautilus, XXI, p. 142, 1908. 



Limncea humilis HERON, Ottawa Nat, I, p. 39, 1880. NYLANDER, Nautilus, 

 VIII, p. 126, 1895; XIII, p. 104, 1900. LERMOND, Shells of Maine, p. 38, 1908 

 (part). 



Lymnea grimthiana LEA, Proc. Amer. Phil. Soc., II, p. 33, 1841 ; Trans. 

 Amer. Phil. Soc., IX, p. 8, 1844 ; Obs., IV, p. 8, 1848. 



Lymncea grimthiana WHEATLEY, Cat. Sh. U. S., Ed. 2, p. 23, 1845. SCUD- 

 DER, Bull. Nat. Mus., 23, pp. 43, 201, 1885. 



Limncea griffithiana BINNEY, Check List, p. 12, 1860; Land and F. W. Sh. 

 N. A., II, p. 66, fig. 107, 1865. TRYON, Amer. Journ. Conch., Ill, p. 196, 1867; 

 Con. Hald. Mon., p. 105 (79), pi. 18, fig. 5, 1872. CLESSIN, Mai. Blatt., n. s. 



III, p. 81, 1881. 



Limncea cubensis CROSSE & FISCHER, PILSBRY, VON MARTENS, etc. (not 

 PFR.). 



