Call — The Unionidce of Arkansas. 55 



chologia Iconica, Vol. XVI, Unio, Plate LXXXIII, Fig. 



442. From Dallas, Texas. 

 The geographic range of this heavy and well marked shell 

 is very wide, extending from western New York to Minnesota, 

 and Iowa, and Kansas; to Texas, east to Mississippi and Ten- 

 nessee. In Arkansas it has been found in the St. Francis 

 river at Wittsburg. 



Unio tuberculatus Barnes. 



Am. Jour. Sci. and Arts, last series, 1823, Vol. VI, p. 

 125, PI. VII, Figs. 8a, 8b; also, figured as Unio verru- 

 cosus Rafinesque, in Poulson's translation of " Monograph 

 of the Bivalve Shells of the river Ohio", 1832, frontis- 

 piece; same, in Chenu, Bibliotheque Conchyliologique, 

 1845, p. 17, PI. II, Figs. 10-12; Reeve, Conchologia 

 Iconica, Vol. XVI, Unio Plate 1, Fig. 4; the figure is 

 that of a fine old male. 

 The range of this form is very great; specimens have been 

 found from western New York to Minnesota, Iowa, and Ne- 

 braska; to Kansas, and central Texas; to Georgia, and Ala- 

 bama. It is commonly abundant wherever found. In the 

 Cahaba river, Alabama, where the shell is very abundant, 

 more than half of those taken have purple nacre. The nacre 

 is usually white, though, in large specimens, it is often 

 blotched with irregularly distributed, brownish spots. 



In Arkansas specimens have been taken in the Saline river, 

 at Benton; in the St. Francis, at Wittsburg. Its great 

 length, nodulous anterior portion, striate, posterior slopes, 

 bi-angulate and compressed posterior, will serve to easily 

 separate it from its congeners. The species was originally 

 described from Wisconsin. 



Unio tumescens Lea. 



Trans. Am. Philos. Soc, 2d series, Vol X, 1845, p. 71, 



PI. Ill, Fig. 7. Described from Alexandria, Louisiana. 



This species was erected on one perfect shell, and one valve 



of a second specimen. The only locality in Arkansas, from 



which specimens were secured, is the Ouachita river, at Ark- 



adelphia. It appears to be very rare. It is also credited to 



