Call — Tlie Unionidoe, of Arkansas. 29 



short, thick, and nodulous, and often exhibits a pinkish tinge 

 within. In the Meramec, White, St. Francis, Saline, and 

 Colorado rivers it is larger, flatter, thinner, less nodulous, or 

 the nodules are less numerous, but the individual ones are 

 much larger and smoother. It is such a shell as this, with 

 absolutely perfect beaks and epidermis, that forms the basis of 

 the figure in the plate. It was collected by Prof. B. W. Ever- 

 man, in the White river, Indiana, and is among the most per- 

 fect full-grown specimens known. The arrow-shaped, green 

 markings are well exhibited in the specimen. 



Conrad, in his Monograph, Plate V, Fig. 2, gives a fine 

 figure of this species. 



Unio multiplicatus Lea. 



Trans. Am. Philos. Soc, 2d series, Vol. IV, 1830-31, 



p. 106, PI. IV, Fig. 2. Reeve, in Conchologia Iconica, 



Unio Plate II, Fig. 8, as Unio lieros Say ; Lea figures the 



animal of his species in Jour. Acad. Nat. Sci. Phila., 2d 



series. Vol. IV, PL 30, Fig. 105. 



Unio hews Say . New Harmony Disseminator, Vol. II, 

 p. 291, 1829; Conrad in Monograph of Unio, PL LIX. 



Unio undulatus Say. American Conchology, 1831, PL 

 XVI, figured from the Fox river, Illinois. This is not 

 the Unio undnlatus Barnes, but Say abandoned his lieros 

 for the name of Barnes thinking the totally dissimilar 

 forms to be identical. 



Unio hoykinianus Lea. Trans. Am. Philos. Soc, 2d 

 series. Vol. VIII, 1840, p. 208, PL XIII, Fig. 22; 

 Reeve, in Conchologia Iconica, Unio Plate I, Fig. 1, 

 1868. Described from the Chattahoochee river, Georgia. 



Unio ellioitii Lea. Jour. Acad. Nat. Sci. Phila., Vol. 

 IV, 2d series, 1858, p. 54, PL VII, Fig. 37. Described 

 in 1856 from Othcalooga creek, Gordon county, Georgia. 



Unio eighfsii Lea. Jour. Acad. Nat. Sci. Phila., 2d 



series, Vol. IV, 1860, Plate LXIV, Fig. 192, p. 367, 



described from Texas and Mexico. 



This is the most ponderous Unio found in American waters. 



It sometimes attains, as in the Ohio river, at Evansville and 



Louisville, the Cumberland, at Nashville, the Alabama, at 



