LYMNAID® OF NORTH AMERICA. 95 
mastus or some allied genus. Dr. White does not mention this species 
in his list of Laramie mollusks in Bulletin 128, U. S. Geological Survey. 
_ LOWER EOCENE LYMNEAS. 
Pleurolimnza tenuicosta (M. & H.). Plate XVI, figures 9-11. 
figures 9-11. 
This species occurs in the Fort Union and Wasatch formations 
of the Lower Eocene Period. See ante, page 92. 
Galba minuscula (White). Plate XVI, figures 16, 17. 
Limnea minuscula Wuite, Proc. U. S. Nat. Mus., III, p. 160, 1880.— 
Mittrr, Journ. Cin. Soc. N. H., IV, p. 133, 1881; Mes. & Cznoz. Geol., p. 275, 
1881—WHiTtTE, 3rd An. Rep. U. S. Geol. Surv., p. 445, pl. 29, figs. 24-25, 1882; 
Bull. U. S. Geol. Surv., no. 128, p. 80, 1895. 
Limnea (Leptolinnea?) minuscula Wuitr, Amer. Journ. Sci. & Arts, 3 
ser., XX, p. 45, 1880; An. Mag. N. H., ser. 5, VI, p. 248, 1880; Bull. U. S. Geol. 
Surv., no. 34, pp. 11, 22, pl. 11, figs. 10-12, 1886. 
“SHELL rather small, moderately attenuate; spire much longer 
than the aperture; volutions six or seven, moderately convex, the distal 
border very narrowly appressed against each preceding coil; aperture 
small, elongate, subovate; columellar fold distinct, but not large. Sur- 
face marked by distinct lines of growth, but no revolving lines have 
been detected. 
“The only two examples of this species that have been discovered 
are broken, but the full length of the larger one is estimated at 9 milli- 
meters; diameter of last volution, 3 millimeters; length of aperture, 
3% millimeters” (White). 
Types: Cotypes, no. 8907. Plesiotype, no. 20065, U. S. Nat. Mus. 
Horizon: Wasatch, Lower Eocene Period; on the confines of 
the Green River (Bridger) and Wasatch formations. 
LocaLity: Three miles east of Table Rock Station, Sweetwater 
County, southern Wyoming; Wales, Utah. 
Remarks: This species is placed in Leptolimnea by White, but 
this disposition seems scarcely correct, as the whorls are not quite 
cylindrical enough to be typical of the group. It resembles elongate 
forms of the recent caperata Say and particularly the Pleistocene 
species anticostiana Dall. Its best disposition would seem to be in the 
subgenus Galba of the genus Galba. 
MIDDLE EOCENE LYMNEAS. 
Galba vetusta (Meek). Plate XVI, figures 12, 13. 
Limnea vetusta MEEK, Proc. Phil. Acad., p. 314, 1860.—Brinney, L. & 
F. W. Sh. N. A., II, p. 72, 1865.—Conrap, Smith. Check List, p. 9, 1866.—MEEk, 
Simpson’s Report, Great Basin, Utah, pp. 367, 373, pl. 5, fig. 3, 1876; Bull. U. S. 
Geol. & Geog. Surv. Terr., III, p. 611, 1877——Wuite, Amer. Journ. Sci. & Arts, 
ser. 3, XX, p. 45, 1880—Mrier, Jour. Cin. Soc. N. H., III, p. 82, 1880; Mes. 
