UPPER TENNESSEE DRAINAGE. 531 



from Grainger Co., Tenn., up the North Fork at Mendota, Washing- 

 ton Co., Va., and Big Moccasin Creek, Scott Co., Va. It has not 

 been found in South Fork Holston, Watauga, or any of the eastern 

 tributaries of the Tennessee, ahhough the var. apprcssa goes to the 

 lower NoHchucky and into the Little River drainage. 



In addition, it is in some of the tributaries of the lower Clinch: 

 in Poplar Creek, Roane Co. (intergrading here with cuneohis ap- 

 pressa) and in Emory River, at Harriman, Roane Co., Tenn. 



Type locality: Holston River, Tenn. (topotypes examined). 



6. FuscoNAiA cuNEOLUS APPRESSA (Lea), 1 87 1. 



Unio appressus Lea, '71. — Unio fiiscumbiensis Lea, '71. — Uiiio 



flavidus Lea, '71. — Pleurohcma tiiscuiiibiensis Simpson, "14, p. 



748. 



There has been great confusion about this form, for the reason 

 that the type-set in the U. S. JMus-. (examined by myself) contains 

 three specimens, of which only one, the figured type, is this, while 

 the other two belong to Lexingtonia dolabelloidcs conradi (Van.). 

 But several authors seem to have taken the latter as the types, and 

 thus, for instance, Pleurohcma apprcssnm Simpson ('14, p. 747) is 

 not this, but Lexingtonia dolabelloides conradi. 



The figured type of Lea is a more swollen form of F. cuneohis, 

 and resembles the latter in every respect except obesity. I have 

 drawn the line between the two at the diameter of 50 per cent, of the 

 length, and specimens with this diameter, and over, I call F. cuneohis 

 appressa. 



This variety belongs to the larger rivers. I have not seen it from 

 the Powell, and in the Clinch it turns up for the first time below the 

 mouth of the Powell, at Offutt, Anderson Co., Tenn., but it goes into 

 a smaller tributary of the lower Clinch, Poplar Creek, Roane Co., 

 associated here with typical cuneohis. In Emory River, only ciuie- 

 olus has been found. In the Holston, appressa turns up first at 

 Austin Mill, Hawkins Co., Tenn., associated and intergrading with 

 typical cuneohis. 1 also found F. cuneohis appressa in the NoH- 

 chucky, at its mouth, and then it seems to be the prevailing form in 

 the Tennessee at and below Knoxville. 



