260 THE CHICAGO ACADEMY OF SCIENCES. 



Lymncea obrussa modicella BAKER, Bull. 111. State Lab. N. H., VII, p. 103, 

 1906. HENDERSON, Univ. Col. Studies, IV, p. 93, 179, fig. 35, 1907. DANIELS, 

 Nautilus, XXII, p. 121, 1909. 



Lymnaa humilis 1 WHEATLEY, Cat. Sh. U S., Ed. 2, p. 23, 1845. LEWIS, 

 Proc. Phil. Acad., 1856, p. 260. COOPER, Amer. Nat., II, p. 486, 1868. WOLF, 

 Amer. Journ. Conch., VI, p. 28, 1870. LEWIS, Proc. Phil. Acad., 1872, p. 102; 

 Proc. Phil. Acad., 1872, p. 109. RHOADS, Nautilus, XVIII, p. 66, 1904. BAKER, 

 Nautilus, XVIII, p. 125, 1905; Amer. Nat, XXXIX, p. 673, 1905. DALL, Alaska 

 Moll., p. 72, 1905 (part). PILSBRY and FERRISS, Proc. Phil. Acad., 1906, p. 161 (?). 

 BAKER, Bull. 111. State Lab. N. H., VII, p. 104, 1906. HENDERSON, Univ. Colo. 

 Studies, IV, pp. 93, 179, 1907. STERKI, Proc. Ohio Acad. Sci., IV, p. 382, 1907.-- 

 JACKSON, Nautilus, XXI, p. 143, 1908. WALKER, Ottawa Nat., XXII, p. 90, fig 

 1, 1908. LERMOND, S'hells of Maine, p. 38, 1908 (part). 



Lymnea humilis DEKAY, Cat. An. N. Y., p. 32, 1839. GIRARD, Proc. Nat. 

 Inst, I, No. 2, p. 81, 1856. LEA, Exp. in Neb., II, pt. 3, p. 724, 1859. ROBERTS, 

 Rep. U. S. Geol. Surv. Wyoming, 1870, p. 468. TODD, Proc. Am. A. A. Sci., 

 XXVII, p. 235, 1878. WALKER and COOLIDGE, Nautilus, XXII, p. 32, 1908. 



Limnaa humilis MIGHELS, Bost. Journ. Nat. Hist., IV, p. 336, 1843. 

 STIMPSON, S'h. N. Eng., p. 52, 1851. CHICKERING, List. S'h. Portland, Me., 1855 

 or 1856. LEWIS, Proc. Bos. Soc. N. H., VI, p. 2, 1856. HIGGINS, Cat. Sh. Colum- 

 bus, p. 6, 1858. BLAND and COOPER, Ann. N. Y. Lye. N. H., VII, p. 370, 1862. 

 WHITEAVES, Can. Nat. & Geol., VIII, p. 103, 1863. CPR., Rep. Brit. Asso., 

 1864, p. 630. HUBBARD and SMITH, Ann. N. Y. Lye. N. H., VIII, p. 152, 1867. 

 TRYON, Amer. Journ. Conch., Ill, p. 196, 1867. ALDRICH, Rep. N. Y. State Col. 

 N. H., XXII, p. 23, 1868. CURRIER, Kent. Sci. Inst. Mis. Pub. No. 1, 1868. 

 BALL, Proc. Bost. Soc. N. H., XIII, p. 248, 1870. SMITH and PRIME, Ann. Lye. 

 N. H., IX, p. 402, 1870. COOPER, Proc. Cal. Acad. Sci., IV, p. 96, 1870. GOULD, 

 Binney's Ed. Inv. Mass., p. 482, 1870. CPR., Smith. Mis. Coll., 1872, p. 116. 

 JEFFREYS, Ann. Mag. N. H., ser. 4, X, p. 247, 1872. BYRNES, L. & F.-W. Sh. 

 Cin., p. 1, 1872. TRYON, Con. Hald. Mon., p. 105 (79), 1872 (part). JEFFREYS, 

 Journ. Conch., I, p. 16, 1874. SMITH, Rep. U. S. Fish. Com., 1874, p. 702. 

 CALKINS, Proc. Ottawa Acad. Sci., 1874, p. 25; Cin. Quart. Journ. Sci., 1, p. 

 323, 1874. YARROW, U. S. Geol. Surv. 100th Merid., V, p. 945, 1875. DAWSON, 

 British N. A. Bound. Com., p. 349, 1875. WALKER and BEECHER, Proc. Ann. 

 Arb. Sci. Asso., p. 45, 1876. Pop. Sci. Mon., X, p. 248, 1876. JONES, Moll, of 

 Nova Scotia, p. 10, 1877. WALKER, Journ. Conch., II, p. 330, 1879. GIBBONS, 

 Journ. Conch., II, p. 133, 1879. CLESSIN, Mai. Blatt, n. s. I, p. 27, 1879 (part). 

 STEIN, Ind. Dept. Stat. & Geol., 1880, p. 458. CALL, Amer. Nat., XV, p. 586, 

 1881. CLESSIN, Mai. Blatt., n. s. Ill, p. 81, 1881 (part). JORDAN, Nova Acta 

 Ksl.-Leop.-Carol Deutsch Akad. Natur., XLV, p. 367, 1883. SAMPSON, Bull. 

 Sedalia N. H. Soc., No. 1, p. 24, 1885. MOORE and BUTLER, Bull. Brookville 

 Soc. N. H., No. 1, p. 43, 1885. CHRISTY, Journ. Conch., IV, p. 347, 1885. WEST., 

 Vega Exped., IV, pp. 166, 220, 1885. STERKI, Nach. Mai. Gesell., XVIII, p. 

 19, 1886. BEAUCHAMP, Sh. N. Y., p. 4, 1886. H. F. CARPENTER, Random Notes, 

 III, p. 86, 1886. MARSH, Conch. Exch., II, p. 110, 1887. SAMPSON, Amer. Nat., 



*As there is no possible means of knowing just what these records of 

 humilis were founded on, they are all assumed to refer to the northern form 

 which is here called modicella. By this treatment all of the references are 

 brought together. Several references from the south (Louisiana, Texas, New 

 Mexico) may have been founded on the true humilis, but the author has not 

 been able to verify them. 



