LYMNiEID^E OF NORTH AMERICA. 185 



Limnaea {Bulimnca) megasoma Bell, Rep. Geol. and Nat. Hist. Surv. 

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



tLymnea megasoma Lord, Nat. in Brit. Col, II, p. 363, 1866. 



Lymncea 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. 



Linmcea megalosoma Sandberger, Conch, de Urw., p. 581, 1873. 



Bulimnca 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. 



Bulimncea 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 Lymnseas are present, but are rather 

 faint; some specimens are strongly malleated; nuclear whorls 1*4 

 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 5-5J4, 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. 



Length. 



Breadth. 



Aperture length. 



Brea< 



Ith. 





43.25 



22.50 



26.25 





12.10 



mill. Type. 





35.50 



20.50 



22.75 





10.50 



" " 





36.00 



21.00 



22.50 





12.25 



" 





40.50 



22.00 



24.50 





13.00 



" 





41.00 



23.50 



24.50 





14.00 



" 





44.00 



21.00 



24.50 





12.50 



" 





41.00 



21.00 



24.00 





12.00 



" 





47.00 



27.00 



21.00 





14.00 



" 





Type : Academy of 



Natural Sciences of 



Philadelphia, 



2 speci 



mens, No. 58388. 















