ORTMANN: monograph of THK NATADES of PENNSYLVANIA. 213 



General distrihxdion: Type locality, Kentucky River (Vanatta) (Rafinesque 

 gives as habitat the Ohio, Wabasli, and Kentucl<y Rivers). 



Simpson (1900) gives its distribution as follows: "Ohio, Tennessee, and 

 Cumberland river systems; peninsula of Michigan; Kansas; Arkansas; Indian 

 Territory; Louisiana." This possibly requires modification with regard to the 

 southwestern range. The most noteworthy feature in its distribution is its absence 

 in the upper Mississippi-drainage. Numerous localities are known from all over 

 Ohio (Sterki, 1907a). In Indiana (Call, 1896a & 1900) it is found practically all 

 over the state, both in the Ohio and Erie drainages, but it is absent in the Lake 

 Michigan-drainage. As our localities show, it occurs also in West Virginia, and 

 is very abundant in the upper Tennessee region. Wilson & Clark (1914) report 

 it from the upper Cumberland River. In verj^ strong contrast to the foregoing 

 is its scarcity in Illinois. In the latter state it is known only in the southern parts 

 and in the Wabash River (Baker, 1906). Simpson extends the range in a south- 

 westerly direction across the Mississippi. (See also Call, 1895, for Arkansas, and 

 Scammon, 1906, for Kansas.) However, the specimens I have seen from Missouri, 

 Arkansas, and Oklahoma are not typical E. fasciolaris, and represent, as has been 

 recognized by Utterback (1916, p. 128) and hinted at by Wheeler (1918, p. 120), a 

 different species. This species is distinct in the rays, which are fine and capillary, 

 and never form blotches."^ 



In a northeasterly direction this species has crossed over into the lake-drainage, 

 going probably bj' way of the IMaumee-route. It has spread over practically the 

 whole lower peninsula of Michigan (as far north as Cheboygan Co.) (See Walker, 

 1892 & 1898). In Lake Erie it has reached New York at Buffalo (Marshall, 

 1895). It is clear that the other locality in New York, Chautauqua Lake, was 

 reached from the upper Allegheny. 



Two records from Wisconsin and Minnesota are undoubtedly in error and 

 already have been dropped by Simpson. 



Genus Obliquaria Rafinesque (1820). 

 Ortmann, 1912, p. 309; Simpson, 1914, p. 329. 



Type Obliquaria reflexa Rafinesque. 

 A monotypic genus. 



'" This species should be called Ellipsaria occidentalis (Conrad) (1836) (Currant River, Arkansas), 

 the synonym of wliich is Ptychobranchus clintonensis Simpson (1900) (Archies Fork of the Little Red 

 River, Clinton, Arkansas). Unio occidentalis of Conrad has been entirely misunderstood by Simpson 

 (1914, p. 112, as Lampsilis occidentalis). The Carnegie Museum possesses material of this form from 

 Missouri, Arkansas, and Oklahoma. Its metropolis is in the Ozark Mountains. 



