588 ORTMANN— NAYADES OF 



80. Truncilla stewardsoni (Lea), 1852. 



Unio steivardsoni Lea,. '52. — Unio stezvardsoni Lewis, '71. — Trun- 

 cilla steivardsoni Simpson, '14, p. 21. 



I think that what Walker ('loa, pi. 3, f. 4) has figured as the 

 J* of T. lezvisi is actually an old J* of stewardsoni. 



A rare species. The Carnegie Museum has specimens from the 

 Tennessee a.t Knoxville, and Lewis reports it from this region ; and 

 there are also specimens from Clinch River, Clinton, Anderson Co., 

 in the Carn. Mus. I found it myself in the Holston, at McMillan 

 and Mascot, Knox Co., and at Holston Station, Grainger Co., Tenn. 

 Type locality: "Chattanooga River, Tenn." There is no such 

 river in Tennessee. Generally, Lea's " Chattanooga River " is the 

 Chattooga River in northern Georgia (tributary to Coosa) ; but in 

 the present instance this cannot be, since this species is not found 

 in the Coosa drainage. 



81. Truncilla LEWisi Walker (1910). 

 Unio foliatus Lewis, '71. — Truncilla leimsi Simpson, '14, p. 20. 



As stated above. Walker's figure of the (^ ('loa, pi. 3, f. 4) prob- 

 ably belongs to T. stezvardsoni. 



I have found a single small male specimen (soft parts examined!) 

 in the Holston, at Holston Station, Grainger Co., Tenn., and another, 

 somewhat larger one, in the Powell, at Combs, Claiborne Co., Tenn. 

 These dififer from the male of T. stezvardsoni by a wider radial fur- 

 row, with the two ridges confining it, more divergent: My speci- 

 mens are not full grown, and even if they should be young females 

 (as Walker suggested after examination of the one from the Hol- 

 ston), they would present to us the shape of the male, as all young 

 females do in the genus Truncilla, exactly as the soft parts of young 

 females resemble those of the males. 



The Carnegie Museum has (from the Hartman coll.) two fe- 

 males, labeled : Tennessee River, Knox Co., Tenn. Lewis gives this 

 form (as U. foliatus) from the Tennessee at Little River Shoals, 

 below Knoxville ; and Walker reports it from Clinch and Holston 

 rivers in. Knox Co. (also from Cumberland River, Burnside, Pulaski 

 Co., Ky., but not found here by Wilson & Clark, '14). 



