LYMN^LLVE OF NORTH AMERICA. 185 



Limneea (Bulimnca) megasoma BELL, Rep. Geol. and Nat. Hist. Surv. 

 Canada, 1879-1880, p. 75, 1881. 



fLymnea megasoma LORD, Nat. in Brit. Col., II, p. 363, 1866. 



Lymnaa megasoma WHEATLEY, Cat. Sh. U. S., p. 23, 1845. JAY, Cat., ed. 

 4, p. 270, 1852. MORSE, Amer. Nat., Ill, p. 651, pi. 11, fig. 1, 1870. HYATT, 

 Amer. Nat. XIV, p. 71, 1880. WHITFIELD, Bull. Amer. Mus. Nat. Hist, I, 

 p. 29, 1881. DALL, Land and F. W. Moll., p. 67, fig. 44, 1905. BAKER, Amer. 

 Nat., XXXIX, p. 676, 1905; Nautilus, XX, p. 36, 1906. LATCHFORD, Nautilus, 

 XX, p. 83, 1906. STERKI, Proc. Ohio State Acad. Sci., IV, p. 381, 1907. 

 WALKER, An. Rep. Geol. Surv. Mich., 1908, p. 290, 1909. COLTON, Proc. Phil. 

 Acad., 1908, p. 421. 



Limnaa megalosoma SANDBERGER, Conch, de Urw., p. 581, 1873. 



Bulimnea megasoma CHENU, Man. Conch., II, p. 480, fig. 3543, 1862. 

 LEWIS, Bull. Buf. Soc. Nat. Hist., II, p. 135, 1874. WETHERBY, Journ. Cin. 

 Soc. Nat. Hi'st, II, p. 93, 1879. GRANT, Rep. Nat. Hist. Surv. Minn., XIV, p. 

 122, 1886; XVI, p. 483, 1888. KEYES, Bull. Essex Inst, XX, p. 70, 1888. 



Bulimn&a megasoma TRYON, Amer. Journ. Conch., I, p. 249, 1865. DALL, 

 Ann. Lye. Nat. Hist, IX, p. 349, 1870. DECAMP, Kent. Sci. Inst., Mis. Pub., 

 No. 5, p. 7, 1881 CALL, Bull. U. S. Geol. Surv., II, p. 383, 1884. 



SHELL : Large, ovate, inflated, bulimiform ; periostracum brown- 

 ish, greenish or olive, with, in many specimens, longitudinal streaks 

 of green, orange, purple or ochraceous ; surface strongly marked with 

 growth lines, which are raised to form wide, flat ridges in some speci- 

 mens ; the spiral, wavy lines of the Lymnaeas are present, but are rather 

 faint; some specimens are strongly malleated; nuclear whorls 1% 

 in number, dark chestnut colored in some specimens, light yellowish 

 horn in others; outline of second whorl shouldered near the suture 

 of the first whorl; texture that of satin finish (pi. XLIX, fig. B) ; 

 whorls 5-5^2, rounded, somewhat flattened at the previous sutures; 

 spire varying from rather pointed to depressed dome-shaped; sutures 

 well impressed; aperture large, subovate, inflated, chestnut brown or 

 dark purple within, occupying from half to two-thirds the length of 

 the entire shell ; peristome thin ; parietal wall with a thin wash of 

 callus which is tightly appressed to the body whorl, completely closing 

 the axis; pillar twisted, forming a raised, prominent ascending plait. 



TYPE: Academy of Natural Sciences of Philadelphia, 2 speci- 

 mens, No. 58388. 



