276 MEMOIRS OF THE CARNEGIE MUSEUM. 



Here it is found in the tributaries of Lake Ontario in New York, and in Hamilton 

 Bay of Lake Ontario in Canada (DeKay, 1843; Marshall, 1895), and reaches the 

 Niagara River and Lake Erie (Marshall). In Lake Erie it extends farther west- 

 wards, along the Canadian (Carnegie Museum) Pennsylvanian and Ohio shores 

 (Sterki, 1907o; Walker, 1913). In Ohio it is found also in tributaries of the lake 

 in Portage Co. (Dean, 1890, Sterki) and Cuyahoga River (Dean, 1890), and in 

 Ottawa River, Lucas Co. (Carnegie Museum). ^^^ Further it is found in Michigan 

 over the whole state (Walker, 1898). Call (1896a) reports it also from the St. 

 Joseph basin in Indiana, but in 1900 (p. 458) he says that no authentic specimens 

 are known from this state. Farther to the south and west it seems to be replaced 

 by the closely allied E. subrostrata (Say). 



The western and the eastern ranges seem to be connected from Lake Erie to 

 the Hudson River by the Erie canal, and it is very likely that this species migrated 

 along this route. ^^^ The direction of the migration probably was from west to 

 east, considering the fact that the only closely allied species, Eurynia subrostrata, 

 is a species of the interior basin. Being a species partial to quiet water, it is only 

 natural that it followed the route of the Erie canal. In this case, however, this 

 migration must have been quite recent, and it must be a very late arrival on the 

 coastal plain, where it has spread in recent times, as far South as Virginia, remaining 

 restricted chiefly in the southern part of its range to the Coastal plain. This has 

 been discussed previously in another paper (Ortmann, 1913a, p. 378 et seq.). 



Eurynia (Eurynia) recta (Lamarck) (1819). 

 Lampsilis recta (Lamarck) Simpson, 1914, p. 95. 



Plate XVI, figs. 12, 13. 

 Records from Pennsylvania: 



Ham, 1891 (western Pennsylvania). 



Clapp, 1895 (Allegheny Co.) 



Marshall, 1895 (Allegheny River, Warren Co.) 



Rhoads, 1899 (Ohio River, Coraopolis, Allegheny Co., and Beaver, Beaver Co.) 



Ortmann, 19096, pp. 190 and 202. 



Characters of the shell: Shell large, solid and heavJ^ Outline subelliptical to 

 sublanceolate, elongated, distinctly over twice (up to two and a half times) as 

 long as high. Anterior margin rounded; lower margin more or less convex. 

 Upper margin nearly straight, passing gradually into the descending posterior 



^^o Sterki saj's: " probably also in the Ohio-drainage, at least along the divide." 

 '" This route is more southern than that of Elliptio violaceus, where the connection does not go 

 through Lake Erie but is more northern. 



