ORTMANN: monograph of the naiades of PENNSYLVANIA. 77 



that this is arbitrary, separating things which are actually connected. However, 

 for practical purposes (naming of specimens) it is a great help, and serves to simplify 

 matters. 



Localities in Pennsylvania represented in the Carnegie Museum: 



Ohio River, Shippingport, Cooks Ferry, and Industry, Beaver Co.; Coraopolis, Allegheny Co. (S. N. 

 Rhoads). 



Beaver River, Wampum, Lawrence Co. (G. H. Clapp & H. H. Smith). 



Mahoning River, Mahoningtown and Coverts, Lawrence Co. 



Allegheny River, Natrona, Allegheny Co.; Aladdin, Godfrey, Johnctta, Kelly, and Templeton, Arm- 

 strong Co.; Walnut Bend, Venango Co.; Hickory, Forest Co.; Warren, Warren Co. 



Cheat River, Cheat Haven, Faj'ette Co. 



Other localities represented in the Carnegie Museum: 



Ohio-drainage: 



Oliio River, Toronto, Jefferson Co., Ohio; Steubenville, Jefferson Co., Ohio (W. F. Graham); St. Marys, 

 Pleasants Co., West Virginia; Portland, Meigs Co., Ohio; Portsmouth, Scioto Co., Oliio; Cincin- 

 nati, Hamilton Co., Ohio (Hartman collection). 



Tuscarawas River, Ohio (Holland collection). 



Tennessee-drainage : 

 Duck River, Columbia, Maury Co., Tennessee (B. Walker, donor). 

 Tennessee River, Florence, Lauderdale Co. (H. H. Smith); Bridgeport, Jackson Co., Alabama (B. 



Walker, donor). 

 Holston River, Noeton, Grainger Co., Tennessee. 

 Clinch River, Edgemoor, Anderson Co.; Black Fox Ford, Union Co., Tennessee. 



West of Mississippi: 

 Iowa River, Iowa City, Johnson Co., Iowa (B. Walker, donor). 

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

 Marais des Cygnes River, Rich Hill, Bates Co., Missouri (W. I. Utterback). 

 James River, Galena, Stone Co., Missouri (A. A. Hinkley). 

 Wliite River, Cotter and Norfolk, Baxter Co., Arkansas (A. A. Hinkley). 

 Black River (H. E. Wheeler) and Spring River (A. A. Hinkley), Black Rock, Lawrence Co., Arkansas. 



From other localities in southern Arkansas (Ouachita River) and in Oklahoma, similar forms are 

 at hand, but I omit them here, since they require further study, cliiefly with regard to their relation to 

 the southwestern forms of P. ohliquum rubrum, which are not at all clear. (See Wheeler, 1918, p. 124.) 



Distribution and Ecology in Pennsylvania (See fig. 8) : In the Ohio and Alle- 

 gheny this form is found associated with tjqiical P. ohliquum. No specimens 

 have come to hand from the Monongahela proper, but it must have existed there, 

 since it turns up in the lower Cheat. In the Allegheny, it goes a great distance 

 beyond the range of P. ohliquum, up to Warren Co., but in this whole region it is 

 associated with, and passes into, P. ohliquum coccineum. It also has entered the 

 Beaver River, and goes even up into the lower part of the Mahoning, passing again 



