232 MEMOIRS OF THE CARNEGIE MUSEUM. 



be studied more closely; the species has not been observed on the Pennsylvanian 

 shores of Lake Erie. 



Westward, it is abundant in Illinois (Baker, 1906), chiefly in the larger rivers, 

 the Ohio, Wabash, Illinois, Spoon, and Kankakee, and also in the Mississippi, 

 where it is also found on the Iowa side, and goes up to southern Wisconsin (Lapham, 

 1860) and Minnesota (Grant, 1886, Holzinger, 1888). 



Thence westward and south westward, records are at hand from Missouri 

 (Utterback, 1916), Kansas (Scammon, 1906). Simpson (1900) also mentions the 

 Arkansas River. The Carnegie Museum has it from Black River in northern 

 Arkansas. 



South of the Ohio it is found in the Kentucky River (type locality) and in the 

 Cumberland (Wilson & Clark, 1914). It was reported from Nashville, Davidson 

 Co., Tennessee, by Marshall (1895). A single specimen is in the Carnegie Museum 

 from the Tennessee in northern Alabama. Farther up above Chattanooga it is 

 absent. I never saw it there, and it is absent in Lewis' list (1871). 



As to its ecology I am able to say from personal experience, that it is a species 

 belonging to the shell-banks of the Ohio, in the deep channels, with strong, steady 

 currents. It is also in the smaller branches in (at low stages) shallow water, in 

 gravel. Scammon (1906) calls it "a lover of water of moderate depth and of sandy 

 river-beds." 



Genus Actinonaias Crosse & Fischer (1893). 



Nephronaias Crosse & Fischer; Ortmann, 1912, p. 324; Actinonaias Frierson, 1917, 

 p. 48.i*« 



Type Unio sapotalensis Lea. 



The only species known from Pennsylvania has been placed by Simpson in 

 Lampsilis. But whatever the final name of the genus may be, it is surely not 

 Lampsilis, because entirely lacking the characteristic structures found in the 

 female in that genus. 



Actinonaias ligamentina (Lamarck) (1819). 

 Lampsilis ligamentina (Lamarck) and Lampsilis ligamentina nigrescens Simpson, 

 1914, pp. 79 and 82. 



Plate XIV, figs. 5, 6. 

 Records from Pennsylvania: 



Harn, 1891 (western Pennsj^lvania). 

 Stupakoff, 1894 (Allegheny Co.). 



"^ Simpson's Nephronaias contains an assemblage of heterogenous species, belonging even to 

 different subfamilies. The nomenclature of this genus is stUl provisional, the structure of the type- 

 species being as yet incompletely known. 



