NO. 1205. SYNOPSIS OF THE NAIADES SIMPSON. 763 



t PLEUROBEMA ARGENTEA Lea. 



*Unio argenteus LEA, Pr. Am. Phil. Soc., II, 1841, p. 82; *Tr. Am. Phil. Soc.. VIII, 

 1843, p. 242, pi. xxv, fig. 57 ; * Obs., Ill, 1842, p. 80, pi. xx v, fig. 57.* CONRAD, 

 Pr. Ac. N. Sci. Phila., VI, 1853, p. 245. *CHENU, 111. Conch., 1858, pi. xxxni, 

 figs. 2, 2a, 2b. H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 495. *KUSTER, 

 Conch. Cab. Unio, 1861, p. 188, pi. LIX, fig. 4 ; 1861, p. 225, pi. LXXVI, fig. 3. 



* SOWERBY, Conch. Icon., XVI, 1868, pi. xxxvn, fig. 204.* B. H. WRIGHT, 

 Check List, 1888. *P.ETEL, Conch. Sam., Ill, 1890, p. 145. 



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



Upper Tennessee Kiver drainage. 



t PLEUROBEMA ARGENTEA var. PANNOSA Simpson. 



* Pleurobema aryentea pannosa SIMPSON, Pr. Ac. N. Sci. Phila., 1900, p. 82. 



A solid, somewhat inflated, roughened form from Hot Springs, Arkan- 

 sas, may be designated as above. Probably a valid species. 



t PLEUROBEMA CONASAUG^NSIS Lea. 



*Unio conasauyainsis LEA, Pr. Ac. N. Sci. Phila., II, 1872, p. 155. Ml. Ac. X. Sci. 

 Phila., VIII, 1874, p. 33, pi. x, fig. 30; *0bs., XIII, 1874, p. 37, pl.x, fig. 30. 

 V B. H. WRIGHT, Check List, 1888. 



Upper Tennessee Eiver drainage. 



t PLEUROBEMA BREVIS Lea. 



'Unio brevis'LEA, Pr. Ac. N. Sci. Phila., II, 1872, p. 157; Ml. Ac. N. Sci. Phila., 

 VIII, 1874, p. 35, pi. xii, fig. 32; *Obs., XIII, 1874, p. 39, pi. xii, fig. 32. 

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



Tennessee Eiver system ; Hardy, Arkansas. 



t PLEUROBEMA BREVIS var. SUBILLIPTICA Simpson. 



* Pleurobema brevis subilliptica SIMPSON, Pr. Ac. N. Sci. Phila., 1900, p. 80. 



A solid, inflated form from Hardy, Arkansas, may bear this name. 

 It is probably a distinct species. 



f PLEUROBEMA PLANIOR Lea. 



*Unio planior LEA, Pr. Ac. N. Sci. Phila., XII, 1868, p. 145; Ml. Ac. N. Sci. 

 Phila., VI, 1869, p. 316, pi. L, fig. 129; * Obs., XII, 1869, p. 76, pi. L, fig. 129. 



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

 *Margaron ( Unio) planior LEA, Syn., 1870, p. 35. 



Upper Tennessee Kiver drainage. 



f PLEUROBEMA ESTABROOKIANA Lea. 



* Unio estabrookianus LEA, Pr. Am. Phil. Soc., IV, 1845, p. 164; *Tr. Am. Phil. 



Soc., X, 1853, p. 77, pi. vi, fig. 17; * Obs., IV, 1848, p. 51, pi. vi, fig. 77. 

 *CONRAD, Pr. Ac. N. Sci. Phila., VI, 1853, p. 248. *H. and A. ADAMS, Gen. 

 Rec. Moll., II, 1857, p. 495. *B. H. WRIGHT, Check List, 1888. 

 *Margaron ( Unio) estabrookianus LEA, Syn., 1852, p. 24; 1870, p. 35. 



* Unio estabroJcianus PJETBL, Conch. 3am., Ill, 1890, p. 152. 



