560 ORTMANN— NAYADES OF 



and Anodonta denigrata Lea, which are this species, have been de- 

 scribed from Campbell Co., Tenn. : this is surely in the Cumberland 

 drainage, since Wilson & Clark report it ('14) from Clear Fork, at 

 Jellico, Campbell Co., Tenn., and other places in the upper Cumber- 

 land region in Kentucky (I found it myself in Cumberland River at 

 Orby, Bell Co., Ky.). 



In the Walker collection are two specimens from Powell River, 

 Lee Co., Va., collected by G. F. Sword. There is no mistake about 

 them, and thus this species must be listed with the upper Tennessee 

 shells, although known only from a single and somewhat indefinite, 

 locality, and remarkable for its absence all over the rest of this 

 region. 



Type locality: Ohio River, Cincinnati, Ohio. 



Genus: Alasmidonta Say (1818). 

 Ortmann, 'i2h, p. 294. 



40. Alasmidonta (Pressodonta) minor (Lea), 1845. 



Margaritana minor Lea, '45. — Margaritana minor Lewis, "72. — 

 Alasmidonta {Pressodonta) minor Ortmann, 'i2h, p. 295. — '14, 

 p. 46 (anatomy). — Alasmidonta minor Ortmann, '13&, p. 311. — 

 Alasmidonta minor Goodrich, '13, p. 94. — Alasmidonta (Presso- 

 donta) minor Simpson, '14, p. 498. 



A characteristic small creek species, locally abundant. It is found 

 all over the region, but strictly avoids the medium-sized and larger 

 rivers. I have never seen it in the Clinch South of the Va.-Tenn. 

 state line, and never in the Holston proper. I know it from the fol- 

 lowing stations. 



South Fork Powell River, Big Stone Gap, Wise Co., Va.. ; North 

 Fork Clinch River, Tazewell, Tazewell Co., Va. (Walker coll.) ; 

 Clinch River, Cedar Bluff, and Richland, Tazewell Co., Va. ; Clinch 

 River, Cleveland, Russell Co., Va. ; Clinch River, St. Paul, Wise Co., 

 Va. ; Clinch River, Speers Ferry, Scott Co., Va. ; Brush Fork (tribu- 

 tary to Poplar Creek and Clinch), Marlow, Anderson Co., Tenn.; 

 Big Mocassin Creek, Mocassin Gap, Scott Co., Va. ; North Fork Hol- 

 ston River, Saltville, Smyth Co., Ya.; Middle Fork Holston River, 



