UPPER TENNESSEE DRAINAGE. 533 



with var. aiialoga). In the same collection are typical cor also from 

 Poplar Creek, Roane Co., a rather small stream, where we should 

 expect the headwaters-form. (It happens, sometimes, that a small 

 tributary of a large river has, at or near its mouth, the large-river 

 form.) Lewis reports this form from the Tennessee below 

 Knoxville. 



Type locality: Elk River, Ala. (and Flint River, Ala.) (topotypes 

 examined, loaned by Frierson). 



Note: Conrad's Flint River is not the one in Madison Co., but the 

 one in Morgan Co., Ala. 



8. FuscoNAiA COR ANALOGA nov. var. 



Uiiio cdgarianus Reeve, Conch. Icon. i6. Unio. 1864, pi. 15, f. 65. — 

 Fusconaia apprcssa or edgariana Goodrich, '13, p. 93. 



This flat form of cor (or cdgarianus) has never been separated 

 from the swollen typical form, probably because there never was any 

 doubt about its afiinity, on account of the peculiar color character 

 of the shell. However, it differs from typical cor as strongly as does 

 F. cuneolus from F . cuneolus appressa, and thus deserves a varietal 

 name. The shell figured by Reeve as U . edgariamis surely is this, 

 since the compressed shape is mentioned. Specimens with the diam- 

 eter less than 50 per cent, of the length fall under this variety. 



This is the form of the headwaters and small streams. It is in 

 the Powell, and goes up to Lee Co., Va. It is in the Clinch, from 

 Needhams Ford, Union Co., Tenn. (Walker coll.) up to Cleveland, 

 Russell Co., Va., and becomes cjuite abundant in the Virginian part 

 of this river. In addition, it is in the North Fork Holston from 

 Hawkins Co., Tenn., up to Holston, Washington Co., Va. 



It has never been found in any other part of the Holston drain- 

 age, or any other river or creek in East Tennessee, and its restric- 

 tion to North Fork Holston, Clinch, and Powell, and its continuation 

 downward, as typical cor, in the Tennessee proper alone, is quite 

 remarkable. 



Type locality: Clinch River, Speers Ferry, Scott Co., Va. (types 

 in Carn. Mus. Cat. no. 61.6326). 



Note: The group of F. cor is also represented in the Tennessee 



