762 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XXII. 



t PLEUROBEMA PYRIFORMIS Lea. 



*Unio pyriformis LEA, Pr. Ac. N. Sci. Phila., IX, 1857, p. 31; * Jl. Ac. N. Sci. 

 Phila., IV, 1858, p. 69, pi. xn, fig. 50; * Obs., VI, 1858, p. 69, pi. xn,flg. 50. 



* B. H: WRIGHT, Check List, 1888. 

 *Margaron ( Unlo) pyriformis LEA, Syn., 1870, p. 40. 



Near Columbus, Georgia. 



t PLEUROBEMA MODICA Lea. 



*Unio modiewsLEA, Pr. Acad. N. Sci. Phila., IX, 1857, p. 171; *Jl.Acad. N. Sci. 



Phila., IV, 1859, p. 204, pi. xxiv, fig. 86; * Obs., VII, 1860, p. 22, pi. xxiv, 



fig. 86.* B. H. WRIGHT, Check List, 1888. 

 *Margaron ( Unto) modicus LEA, Syn., 1870, p. 40. 



Chattahoochee River, Georgia. 



t PLEUROBEMA STRIATA Lea. 



*Unio striatus LEA, Pr. Am. Phil. Soc., I, 1840, p. 287; * Tr. Am. Phil. Soc., VIII, 

 1843, p. 203, pi. xn, fig. 16 ; * Obs., Ill, 1842, p. 41, pi. xn, fig. 16.* CONRAD, 

 Pr. Acad. N. Sci. Phila., VI, 1853, p. 258.* H. and A. ADAMS, Gen. Rec. Moll., 

 II, 1857, p. 496. * CHENU, 111. Conch., 1858, pi. xxix, figs.l, la, 16. *B. H. 

 WRIGHT, Check List, 1888. 



*Margaron (Unio) striatm LEA, Syn., 1852, p. 26; 1870, p. 40. 



Chattalioochee River, Georgia. 



t PLEUROBEMA GIBBER Lea. 



* Unio gibber LEA, Tr. Am. Phil. Soc., VI, 1838, p. 34, pi. X, fig. 30; * Obs., II, 1838, p. 



35, pi. x, fig. 30.* TROSCHEL, Arch, fur Naturg., V, 1839, Pt. 2, p. 236. 

 *HANLEY, Test. Moll., 1842, p. 185; * Biv. Shells, 1843, p. 185, pi. xxi, fig. 46. 



* CATLOW and REEVE, Conch. Norn., 1845, p. 59. * CONRAD, Pr. Acad. N. Sci. 

 Phila., VI, 1853, p. 250.* H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 495. 



* CHENU, 111. Conch., 1858, pi. xxin, figs. 2, 2a, 26. * SOWERBY, Conch. Icon., 

 XVI, 1866, pi. XL, fig. 219.* B. H. WRIGHT, Check List, 1888. 



* Margarita ( Unio) gibber LEA, Syn., 1836, p. 20; 1838, p. 17. 

 *Margaron ( Unio) gibber LEA, Syn., 1852, p. 24 ; 1870, p. 37. 



Caney Fork, Tennessee. 



t PLEUROBEMA FASSINANS Lea. 



* Uniofassinans LEA, Pr. Ac. N. Sci. Phila., XII, 1868, p. 143 ; * Jl. Ac. N. Sci. Phila., 



VI, 1869, p. 305, pi. XLVII, fig. 118; *Obs., XII, p. 65, pi. XLVII, fig. 118. * B. 

 H. WRIGHT, Check List, 1888. 

 *Margaron ( Unio) fassinans LEA, Syn., 1870, p. 42. 



fPLEUROBEMA FASSINANS var. RHOMBOIDEA Simpson. 1 



Upper Tennessee River drainage. 



'A form of what I consider fassinans is abundant in the Clinch River, in western 

 Virginia, which is considerably more rhomboid than the type and may be called var. 

 rhomboidea. 



