﻿TRUNCIU<A 17 



Tennessee and Cumberland River drainage. 



Type locality, Cumberland River. 

 Unio haysianus Lea, Tr. Am. Phil. Soc, V, 1833, p. 35, pi. m, 



fig. 7 ; Obs. I, 1834, p. 147, pi. Ill, fig. 7.— KusTER, Conch. 



Cab. Unio, 1856, p. 209, pi. i^xix, fig. 4.— Reeve, Conch. 



Icon., XVI, 1864, pl- XV, fig. 62. 

 Margarita (Unio) haysianus Lea, Syn., 1836, p. 22; 1838, p. 18. 

 Margaron (Unio) haysianus Lea, Syn. 1852, p. 26; 1870, p 41. 

 Scalenaria haysiana Agassiz, Arch, fiir Naturg., I, 1852, p. 48. 

 Truncilla haysiana Simpson, Syn., 1900, p. 520. 

 Unio sowerhyanus Lea, Tr. Am. Phil. Soc, V, 1839, P- 68, 



pi. X, fig. 28; Obs. I, 1834, p. 180, pi. X, fig. 28.— Conrad] 



Monog., VIII, 1837, p. 66, pi. xxxvii, fig. i.— Kuster, 



Conch. Cab. Unio, 1852, p. 62, pi. xiv, fig. 3.— Reeve, Conch. 



Icon., XVI, 1864, pl- XIV, fig. 58. 

 Margarita (Unio) sowerhyanus Lea, Syn., 1836, p. 20; 1838, 



p. 17. 

 Margaron (Unio) sozverbyanus Lea, Syn., 1852, p. 25 • 1870 



p. 38. 



The male and female shells of this differ a good deal as they 

 do in nearly all the species of Truncilla. The male shell is 

 subtriangular, as high or higher than it is long and the radial 

 furrow in front of the posterior ridge is not very pronounced. 

 Its posterior end shows vestiges of teeth along the growth 

 lines but nothing like so distinctly as does the female shell, 

 which is small, less high than long and suborbicular. 



Lea described the female of this species as Unio haysianus 

 and the male as Unio soiiferbyanus in the same paper, the 

 former having precedence. 



Trunciixa othcaloogensis (Lea). 



Shell subquadrate, solid, inflated, inequilateral, nearly 

 smooth with shining straw-colored epidermis, the hinder part 

 with feeble radiating sculpture; hinge line a little arched; 

 base nearly straight; anterior end rounded; posterior end al- 

 most squarely truncated above, rounded below; pseudocardi- 

 nals elevated, subcompressed, ragged, two in each valve; lat- 



