ORTMANN: monograph of the naiades of PENNSYLVANIA. 243 



Meramec River, Meramec Highlands, St. Louis Co., Missouri (N. M. Grier). 

 Hinkston Creek, Columbia, Boone Co., Missouri (D. K. Greger). 

 Missouri River, St. Joseph, Buchanan Co., Missouri (W. I. Utterback). 

 Black River, Black Rock, Lawrence Co., Arkansas (H. E. Wheeler). 

 Ouachita River, Arkadelphia, Clark Co., Arkansas (H. E. Wheeler). 



Alabama-drainage: 

 Coosa River, Weduska Shoals, Shelby Co.; Riddles Bend, Cherokee Co., Alabama (H. H. Smith). 



Distribution and Ecology (See fig. 25) : Type locality, Ohio (Lea). 



In Pennsylvania this species has been found only in the Ohio m Allegheny 

 County. It seems to cover about the same range as A. truncata (See Simpson, 

 1900). It goes from Lake Erie down the Ohio, and its tributaries, and up the 

 Mississippi to Minnesota, and westward and southward down and across the Missis- 

 sippi to Kansas, Oklahoma, and eastern Texas. But in addition it has been re- 

 ported from Alabama (Simpson) and Coosa River (Call, 1885), and its presence in 

 the latter river is confirmed by specimens in the Carnegie Museum. 



It has been referred to as a mud-loving shell by Baker (1898), and as an in- 

 habitant of sand-bars by Call (1900), and of the sandy and muddy beds of rivers, 

 avoiding smaller streams, by Scammon (1906). 



Genus Plagiola Rafinesque (1820).^^^ 

 Ortmann, 1912, p. 329; Simpson, 1914, p. 302. 



Tjqie Ohliquaria lineolata Rafinesque. 

 MonotjTDic genus. 



Plagiola lineolata (Rafinesque) (1820). 

 Plagiola securis (Lea) Simpson, 1914, p. 304; Plagiola lineolata (Rafinesque) 

 Vanatta, 1915, p. 553.1^^ 



Plate XIV, fig. 10, Plate XV, figs. 1, 2, 3. 

 Records from Pennsylvania: 



Ham, 1891 (western Pennsylvania). 



Clapp, 1895 (Allegheny Co.). 



Rhoads, 1899 (Ohio River, Coraopolis, Allegheny Co.). 



Ortmann, 19096, p. 192. 



Characters of the shell: Shell rather large, heavy and solid. Outline triangu- 

 larly-ovate, generally slightly longer than high. Anterior margin rounded, curving 

 into the lower margin, which is less convex, or nearly straight in its posterior part. 



'^2 Not 1819. It was published in 1819 as " nomen nudum." 

 1" See also Walker, 1916, p. 45. 



