LYMN^ID^E OF NORTH AMERICA. 137 



52.00 31.00 32.50 20.00 " Elba River, Germany. 

 38.00 19.00 21.50 9.00 " 



Range : Circumboreal ; North America north of about the 40th 

 parallel ; Europe, the Caucasus, northern and western Asia. 



Remarks : Stagnalis is one of the most characteristic as it is the 

 largest of the Lymnseas. No examples approaching the typical form 

 as found in Europe have been seen by the writer except several speci- 

 mens in the Smithsonian Institution from Slave River, 25 miles below 

 Peace River, Athabaska (No. 180204) and from Lake Harrison, lat. 

 70° north (No. 25913). These specimens are scarcely typical enough 

 to be retained under stagnalis, however, and would seem to more 

 logically range under the variety appressa of Say, to which the majority 

 of American stagnalis should be referred. The specimens from the 

 United States and Canada are easily referred to appressa, but those 

 occurring in the northwestern part of British America and in Alaska 

 are more like the typical form, showing the influence of the Siberian 

 fauna and clearly indicating that stagnalis is a migrant from Asia via 

 the ancient land connection at Bering Strait. The American specimens 

 differ from the typical form in the shape of the body whorl and in 

 the form of the spire, besides in other minor points. 



Lymnaea stagnalis appressa (Say). Plate XIX, figures 4-10; 

 plate XX, figures 1-6; plate XXII, figures 1-3. 



Lymnceus appressus Say, Journ. Phil. Acad., II, p. 168, 1818 ; Binney's 



Reprint, p. 66, 1858. 

 Lymncza appressa Gould., Lamarck's Genera, p. 69, 1833. — Lea, Proc. Amer. 

 Phil. Soc, IX, p. 8, 1841.— Wheatley, Cat. Sh. U. S., p. 23, 1845.— 

 Lea., obs., IV, p. 8, 1848.— Jay, Cat. ed. 4, p. 268, 1852.— Lewis, 

 Proc. Phil. Acad., 1856, p. 259.— Reeve, Elements of Conch., p. 178, 

 I860.— Lewis, Proc. Phil. Acad., 1860, p. 17.— Morse, Amer. Nat., 

 Ill, p. 651, pi. 11, fig. 2, 1870.— Scudder, Bull. U. S. Nat. Mus., 23, 

 p. 200, 1885. 

 Lymncea stagnalis appressa Baker, Amer. Nat. XXXIX, p. 667, figs, 3, 4, 

 1905; Trans. St. Louis Acad., XVI, p. 10, 1906; Bull. 111. State Lab. 

 N. H., VII, p. 102, 1906.— Henderson, Univ. Colo. Studies, IV, pp. 

 93, 179,, 1907.— Daniels, Nautilus, XXII, p. 120, 1909.— Walker, 

 An. Rep. Geol. Surv. Mich., 1908, p. 289, pi. 63, fig. 4, 1909. 

 Lymnea appressa Dekay, Cat. N. Y. Animals, p. 32, 1839. — Currier, Shells 



Grand River, Mich., 1859. 

 Limnea appressa Haldeman, Mon. Limn., p. 18, pi. 5, 1842. — Dekay, Moll. 

 N. Y., p. 74, 1843.— Miles, Geol. Surv. Mich., p. 237, I860.— Cat. Nat. 

 Hist. Eth. Prov. Mus. Victoria, p. 95, 1898. 

 Limncea appressa Beck, Index, p. 113, 1837. — Adams, Amer. Journ. Sci., i, 

 XL, p. 267, 1841; Thomp. Hist. Ver., pt. 1, p. 153, 1842.— Stimpson, 

 Shells of New England, p. 52, 1851.— Moq.-Tand., Moll. France, 

 II, p. 471, 1855.— Binney, Check List, p. 12, 1860; Proc. Phil. Acad., 



