ORTMANN: monograph of the naiades of PENNSYLVANIA. 13 



Othe7- localities represented in the Carnegie Museum: 



Mahoning River, Ohio (Hartm.an collection) (Topotypc). 



Tuscarawas River, Ohio (Holland collection). 



West Fork River, Lynch Mines, Harrison Co., West Virginia. 



Little Kanawha River, Grantsville, Calhoun Co., West ^■irginia (W. F. (irahain). 



Distribution and Ecology in Pennsylvania (See fig. 2) : The di.stribution of thi.s 

 form in Pennsylvania clearly indicates that it is the representative of F. subrotunda 

 in the smaller rivers and creeks, but that it passes in the downstream direction 

 into the latter, and is associated with it in the larger rivers. Its metropolis is in 

 the Beaver system and French Creek. In these it is practically everywhere, and 

 lives in coarser or finer gravel, even in sand, and in more or less rapidly flowing 

 water. It avoids, however, the extreme headwaters, and is not found in the 

 Shenango above Clarksville, and not in French Creek above Cambridge Springs. 

 The records from some smaller tributaries (Pymatuning Creek and Conneaut 

 Outlet) are founded upon single individuals. 



In the larger rivers, the Allegheny, Monongahela, and Ohio, it is also present, 

 but its place is gradually taken b}^ the typical F. subrotunda. From Cooks Ferry 

 in Beaver County down the Ohio to Portsmouth, Scioto County, Ohio, the typical 

 form alone is present. Exceptionally large and posteriorly produced specimens 

 may exhibit the dimensions of kirtlandiana, but such are very rare in this section 

 of the river, and generally it is clearly evident that they were typical subrotunda, 

 when young. 



General Distribution. Type locality, Mahoning River, Ohio (Lea) . 



This variety appears to be restricted to the tributaries of the upper Ohio 

 in West Virginia, Ohio, and Pennsylvania. The river which forms its tj^pe locality 

 in Ohio also contains it in Pennsylvania, and it occurs also in the other branches 

 of the same river-system (the Shenango and Beaver). I further have ascertained 

 that it is found in French Creek, and the upper Monongahela, its range going 

 down for some distance into the larger rivers. I also found it in the Little Kanawha 

 in West Virginia. 



Simpson (1900) quotes it from the " Ohio, Cumberland and Tennessee River 

 systems, southwest to Ai-kansas, north to Wisconsin (?), east through southern 

 Michigan." I think that this wide range is entirely erroneous. Looking over 

 the literature we find it reported from Ohio (aside from the ]Mahoning River) 

 from the Ohio itself and some of its tributaries, especially from the Tuscarawas 

 River (Sterki, 1907a). Further it is mentioned from the Grand River in [Michigan 

 (Call, 1885, and Walker, 1892 and 1898), and from Waukesha, Waukesha Co., 



