ORTMANN: monograph of the naiades of PENNSYLVANIA. 245 



are: 0.26 X 0.35 mm.; those of Lefevi-e & Curtis, 0.23 X 0.31; those of Surber: 

 0.230 X 0.330. 



Breeding season: I have the following dates for gravid females: Sept. 10, 1908; 

 Sept. 12, 1908; Sept. 23, 1908; Sept. 24, 1910; Sept. 25, 1908; Oct. 3, 1908; 

 Nov. 4, 1914; Nov. 17, 1917. Fm-thermore: Febr. 6, 1911; June 14, 1911; 

 June 20, 1911; June 21, 1911; July 13, 1911. In every case glochidia were present, 

 and on the three days in June, discharging females were present. On Jul}'' 13 

 only a single individual, having almost entirely discharged the glochidia, was found. 

 Thus the species is clearly bradytidic, and the breeding season probably begins in 

 August and lasts till June or July of the next year. The interim would include 

 part of July and August. Surber's observations agree with this. 



Remarks: This species is easily recognized and not liable to be confounded 

 with any other. The subtriang-ular, compressed shape, with a narrow posterior 

 truncation, and the peculiar color-pattern, are very distinctive characters. The 

 females are quite variable in shape and the compression of the shell is not so striking. 



Localities in Pennsylvania represented in the Carnegie Museum: 



Oliio River, Smiths Ferry (W. F. Graham), Cooks Ferry, Shippingport, and Industry Beaver Co.; and 



Neville Island, Allegheny Co. (W. F. Graham). 

 Allegheny River, Godfrey and Kelly, Armstrong Co. 

 Monongahela River, Westmoreland Co., and Charleroi, Washington Co. (G. A. Ehrmann). 



Other localities represented in the Carnegie Museum: 



Ohio-drainage: 

 Oliio River, Toronto, Jefferson Co., Ohio; .Beach Bottom, Brook Co., West Virginia (W. F. Graham); 

 Clarington, Monroe Co., Ohio; St. Marys, Pleasants Co., West Virginia; Parkersburg, Wood Co., 

 West Virginia; Portland, Meigs Co., "Ohio; Portsmouth, Scioto Co., Ohio. 



Cumberland- and Tennessee-drainages: 

 Cumberland River, Burnside, Pulaski Co., Kentucky (B. Walker, donor). 

 Tennessee River, Florence, Lauderdale Co., Alabama (H. H. Smith); Knoxville and Brabsons Ferry, 



Knox Co., Tennessee. 

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

 Clinch River, Offutt, Anderson Co., Tennessee. 



Mississippi river and westward: 

 Mississippi River, Muscatine, Muscatine Co., Iowa (Hartman collection). 

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

 Neosho River, Burlington, Coffey Co., Kansas (R. L. Moodie); Miami, Ottawa Co., Oklahoma (F. B. 



Isely). 

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

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

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



