ORTMANN: monograph of the naiades of PENNSYLVANIA. 251 



Tennessee-drainage : 

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

 Shoals Creek, Lauderdale Co., Alabama (H. H. Smith). 

 Paint Rock River, Paint Rock, Jackson Co., Alabama (H. H. Smith). 

 Tennessee River, Knox Co., Tennessee (Smith collection). 

 Nolichucky River, Chunns Shoals, Hamblen Co., Tennessee. 

 Holston River, Mascot, Knox Co.; Hodges, Jefferson Co.; Turley Mill, Noeton, and Holston Station, 



Grainger Co., Tennessee. 

 Clinch River, Edgemoor, Anderson Co.; Clinch River Station, Claiborne Co., Tennessee. 

 Powell River, Combs, Claiborne Co., Tennessee. 



Mississippi River and westward: 

 Mississippi River, Muscatine, Muscatine Co., Iowa (Hartman collection); Moline, Rock Island Co., 



Illinois (P. E. Nordgren). 

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

 Kansas River, Lawrence, Douglas Co., Kansas (R. L. Moodie). 

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

 Spring River, Williford, Sharp Co., Arkansas (H. E. Wheeler). 

 Saline River, Benton, Saline Co., Arkansas (H. E. Wheeler). 

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

 North Fork Canadian River, Weleetka, Okfuskee Co., Oklahoma (F. B. Isely). 

 Bayou Pierre, De Soto Parish, Louisiana (L. S. Frierson). 



Alabama-drainage: 

 Buttahatchee River, Hamilton, Marion Co., Alabama (H. H. Smith). 



Black Warrior River, Tuscaloosa, Tuscaloosa Co.; Squaw Shoals, Jefferson Co., Alabama (H. H. Smith). 

 Valley Creek, Toadviue, Jefferson Co., Alabama (H. H. Smith). 

 Coosa River, Wetumpka, Elmore Co.; near Yellow-Leaf Creek, Chilton Co.; Weduska Shoals and 



Peckerwood Shoals, Shelby Co.; Coosa Valley and Riverside, St. Clair Co.; Minnesota Bend, 



Cherokee Co., Alabama (H. H. Smith). 



Distribution and Ecology in Pennsylvania (See fig. 26) : In Pennsylvania, this 

 species has two ranges. On the one hand it belongs to the three large rivers, 

 without, however, going into their tributaries. In the Allegheny it goes only as 

 far as southern Armstrong Co., where it is very rare; in the Monongahela, it has 

 been found only in Westmoreland Co. (opposite Charleroi). On the other hand 

 P. fragilis occurs in Lake Erie, where it is rather abundant in Presque Isle Bay. 

 Here it apparently finds most congenial conditions on the sandy shores in from 

 one to three feet of water; but it also has been obtained by the sand-sucker from a 

 depth of ten to fifteen feet. 



In the Ohio and Allegheny I found this species chiefly in riffles. Here it is a 

 lively shell, crawling around frequently, and with a speed unusual in other sheUs. 

 The sheUs are here not very perfect, and often more or less injured or stunted. 



General distribution: Type locality, Ohio River (Rafinesque) (Vanatta says: 

 "creeks in Kentucky"). 



