UPPER TENNESSEE DRAINAGE. 659 



region. However, in the collection of B. Walker, there are two large 

 specimens of a form of Anodonta grandis Say, collected by Mr. M. 

 D, Barber, of Knoxville, in a " small mud pond near French Broad 

 River, 8 miles above Knoxville." The largest has a length of i68 

 mm., the other of 127 mm. In the latter, the beak sculpture is vis- 

 ible, and corresponds to that of A. grandis; it has white nacre, and 

 much resembles specimens of the var. gigantea Lea, as found in 

 western Pennsylvania. The other (larger) is a little distorted and 

 tapering behind, and has pale purple nacre, resembling in these char- 

 acters some of the southern forms of the species. 



The occurrence of this form in this isolated locality is quite re- 

 markable, but supports the view that Anodontas may possess excep- 

 tional means of dispersal. According to more detailed information 

 obtained by Mr. Walker in 19 16 from Mr. Barber, the pond is 

 "plainly natural, some 4 or 5 rods long by 2 rods wide, with soft 

 deep mud. There was a small stream of water running to the 

 French Broad River, just a short distance. This was 10 or ii years 

 ago." " Two years ago, I took a nephew and found the same pond, 

 but although we waded the pond in every direction, up to our knees 

 in mud, we could not find even a fragment of gigantea. A man liv- 

 ing near there said he had seen large shells in another pond near, 

 but I have not examined it." These ponds, a short distance from the 

 river, probably are on the flood plain of French Broad; the writer 

 has not been able to locate them on the U. S. Geol. Surv. maps. 



Type locality: Port Gibson, Claiborne Co., Miss. 



Genus: Anodontoides Simpson (1898). 

 Ortmann, 12b, p. 294. 



39. Anodontoides ferussacianus (Lea), 1834. 



Anodonta ferussaciana Lea, '34. — Anodontoides ferussacianus Ort- 

 mann, '12&, p. 294 (anatomy). — Anodontoides ferussacianus 

 Simpson, '14, p. 467. 



Anodonta oblita ( ?) Lewis, '71, may possibly stand for this 

 species. Lewis doubtfully reports this from the Tennessee below 

 Knoxville, but this probably is a mistake. Originally, A. oblita Lea 



