UPPER TENNESSEE DRAINAGE. 575 



Type locality: Cumberland River (not reported from the Cum- 

 berland drainage by Wilson & Clark, '14). 



Genus: jNIedionidus Simpson (1900). 

 Ortmann, 'i2h, p. 334; '15, p. 143. 



63. Medionidus plateolus (Rafinesque), 1831. 



Unio plateolus Rafinesque, '31. — Unio conradicns Lewis, '71. — Unio 

 conradianns Pilsbry & Rhoads, '96. — Medionidus conradicus Ort- 

 mann, 'i2h, p. 335, and '15, p. 142 (anatomy). — Medionidus con- 

 radicus Ortmann, '13&, p. 311. — Medionidus conradicus Good- 

 rich, '13, p. 94. — Medionidus conradicus Simpson, '14, p. 247. 

 The identity of U. plateolus and conradicus Lea ('34) has been 

 suggested to me by Frierson, and I think, this is correct. 



Very abundant in the headwaters and in small streams generally, 

 but quite rare in the larger rivers. It has been found practically all 

 over our region, and often goes up into the smallest streams which 

 contain at all Nayades. It is hardly worth while to record single 

 localities, and it suffices to say that it is in the Powell, Clinch, and 

 Holston, and their tributaries ; in the French Broad, it goes up to 

 Asheville, N. Car. ; it is in Little River, and in South Chickamauga 

 Creek, Ga. From the Tennessee proper, below Knoxville, it has 

 been reported by Lewis. 



Type locality: Falls of the Cumberland River. (Its existence at 

 this place, below the falls, has been confirmed by Wilson & Clark, 

 '14.) 



Genus: Eurynia Rafinesque (1820). 



Ortmann, '12b, p. 336. 



64. Eurynia (Micromya) fabalis (Lea), 1831. 



Unio fabalis Lea, '31. — Unio fabalis Lewis, '71. — Eurynia (Mi- 

 cromya) fabalis Ortmann, '12b, p. 339 (anatomy). — Eurynia 

 fabalis Goodrich, '13, p. 94. — Micromya fabalis Simpson, '14, 



P- 33- 



Rather rare, but possibly in part overlooked. Lewis gives it 

 from Tennessee River, below Knoxville, and the Walker collection 



