68 MEMOIRS OF THE CARNEGIE MUSEUM. 



Ten nessee-drain age : 

 Tennessee River, Florence, Lauderdale Co., Alabama (H. II. Smith). 

 French Broad River, Boyd Creek, Sevier Co., Tennessee. 

 Holston River, McMillan and Mascot, Knox Co.; Hodges, Jefferson Co.; Holston Station, Grainger 



Co., Tennessee. 

 North Fork Holston River, Rotherwood, Hawkins Co., Tennessee. 

 Clinch River, Solwaj^ Knox Co.; Edgemoor, Clinton, and Offutt, Anderson Co.; Black Fox Ford, 



Union Co.; Clinch River Station, Claiborne Co.; Oakman, Grainger Co., Tennessee; Clinchport, 



Scott Co., Virginia. 

 Powell River, Combs, Claiborne Co., Tennessee. 



West of Mississippi: 

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



Distribution and Ecology in Pennsylvania (See fig. 7) : This species is found in 

 Pennsylvania, preeminently in the Ohio and Allegheny Rivers; from the localities 

 in the Monongahela and Beaver, only single individuals are known. It prefers 

 riffles with coarse gravel and strong current, and in Beaver Co. it is found upon 

 the shell-banks in a strong and steady current. The same is true farther down 

 the Ohio, where it is often obtained by the clam-diggers. 



General distribution: Type locality, Falls of the Ohio (Rafinesque) at Louis- 

 ville, Kentucky. 



In the Allegheny River, at Templeton, Armstrong Co., and in the Mononga- 

 hela, in Washington and Westmoreland Cos., Pennsylvania, this species reaches 

 its highest points of advance in an upstream direction. Also Beaver River at 

 Wampum, Lawrence Co., is an extreme point. Farther westward, its range 

 follows the Ohio, and embraces, according to Simpson (1900), the Ohio, Cumber- 

 land, and Tennessee river-systems; west to Missouri and Minnesota. In the upper 

 Ohio, it goes very Httle into the tributaries, and is known only from the Tuscarawas 

 and Scioto in Ohio (Sterki, 1907o«'), Wabash (Call, 1896o and 1900), and White 

 River (Lea, Obs. X, 1863, p. 432) in Indiana. In Illinois it covers, a large territory 

 (Illinois River up to Kankakee and Fox Rivers) . It also follows up the Mississippi 

 and its tributaries in northern Illinois and eastern Iowa (Des Moines River, Witter, 

 1878, CaU, 1885), and goes as far as Minnesota (Grant, 1886, and Holzinger, 1888). 



West of the Mississippi, records are scarce or doubtful,^" but the Carnegie 

 Museum has it from the Meramec River, near St. Louis, and Utterback (1916) 



" Sterki gives also the Mahoning River. I question this record, since I have never seen a trace of 

 it in the lower Mahoning in Pennsylvania, and since Dean (1890) does not mention it. 



''"' Scammon gives it as rare from Verdigris River in Kansas. A specimen from Wakarusa River, 

 LawTcnce, Douglas Co., Kansas, determined by Scammon as P. asopus, and sent to the Carnegie Museum 

 by R. L. Moodie, agrees very well with Scammon's figure (1908, pi. 78, fig. 2) but it is not this species. 

 Our specimen is an old, dead shell, and probably an abnormal Quadrula quadnda. 



