OF NORTH AMERICA. 285 



from Thomaston and Unity, Maine, seem referable to this variety. A 

 form of obrussa occurs at Castle Hill, Aroostook County, which some- 

 what resembles this variety, differing in having a larger aperture and 

 a narrower body whorl. These are probably transition forms. Penin- 

 sula will probably be found in collections labeled desidiosa. 



Galba obrussa exigua (Lea). Plate XXXII, figures 7-14. 



Lymnea exigua LEA, Proc. Amer. Phil. Soc., II, p. 33, 1841; Trans. Amer. 

 Phil. Soc., IX, pp. 9, 10, 1844; Obs., IV, pp. 9, 10, 1848; Proc. Phil. Acad., VIII, 

 p. 81, 1856 ; Journ. Phil. Acad., VI, pp. 155, 162, 1866 ; Obs., XI, pp. Ill, 118, 1867. 



Lymncea exigua WHEATLEY, Cat. Sh. U. S., p. 23, 1843. LEA, Proc. Phil. 

 Acad., 1856, p. 81. CPR., Rep. Brit. Asso., 1864, p. 634. WOLF, Amer. Journ. 

 Conch., VI, p. 28, 1870. CPR., Smith. Mis. Pub., 1872, p. 120. SCUDDER, Bull. 

 Nat. Mus., 23, pp. 33, 43, 201, 1885. 



Limncea exigua D'URBAN, Geol. Surv. Can. Rep. Prog., p. 242, 1859. BIN- 

 NEY, Check List, p. 12, 1860; L. & F.-W. Sh. N. A., II, p. 65, fig. 105, 1865. 

 WHITEAVES, Can. Nat. & Geol., VIII, p. 103, 1863. TRYON, Amer. Journ. Conch., 

 Ill, p. 196, 1867. CLESSIN, Mai. Blatt., n. s., Ill, p. 81, 1881. 



Limnophysa humilis var. exigua COOPER, Proc. Cal. Acad. Sci., IV, p. 96, 

 1870. 



Lymnea plica LEA, Proc. Amer. Phil. Soc., II, p. 33, 1841; Trans. Amer. 

 Phil. Soc., IX, pp. 8, 9, 10, 1844; Obs., IV, pp. 8, 9, 10, 1848; XI, p. 118, 1867; 

 Journ. Phil. Acad., VI, p. 162, 1866. 



Lymncea plica WHEATLEY, Cat. Sh. U. S., p. 23, 1843. SCUDDER, Bull. Nat. 

 Mus., 23, pp. 33, 44, 201, 1885. 



Limncea plica BINNEY, Check List, p. 12, 1860; L. & F.-W. Sh. N. A., II, 

 p. 65, fig. 103, 1865. TRYON, Amer. Journ. Conch., Ill, p. 196, 1867. CLESSIN, 

 Mai. Blatt, n. s., Ill, p. 81, 1881. 



Limncea plicata D'URBAN, Geol. Surv. Can., Rep. Prog., p. 242, 1859. 



Lymncea obrussa plica BAKER, Bull. 111. State Lab. N. H., VII, p. 103, 1906. 



Lymnea planulata LEA, Proc. Amer. Phil. Soc., II, p. 33, 1841; Trans. Amer. 

 Phil. Soc., IX, p. 9, 1844 ; Obs., IV, p. 9, 1848. 



Lymncea planulata WHEATLEY, Cat. Sh. U. S., p. 23, 1843. SCUDDER, E '"'. 

 Nat. Mus., 23, pp. 33, 44, 201, 1885. 



Limncea planulata BINNEY, Check List, p. 12, 1860; L. & F.-W. Sh. N. A., 

 II, p. 65, fig. 104, 1865. CLESSIN, Mai. Blatt., n. s., Ill, p. 81, 1881. 



SHELL: Small, turreted, subfusiform, generally narrow; surface 

 dull to shining, growth lines coarse, elevated, crowded; spiral lines 

 sometimes present ; whorls 5, generally well rounded, slowly increasing 

 in diameter; spire wide, elevated, turreted, generally longer than the 

 aperture; nuclear whorls as in obrussa; sutures deeply impressed; 

 body whorl generally compressed, subcylindrical ; aperture ovate to 

 elliptical, slightly effuse; outer lip thin; inner lip narrow, tightly ap- 

 pressed at its junction with the parietal wall, the lower part erect or 

 turned upward ; umbilical chink very small, frequently entirely closed. 



