58 Trans. Acad. Sci. of St. Louis. 



Unio satur Lea. Trans. Am. Philos. Soc, 2d series, 

 Vol. X, 1852, p. 265, PI. XVII, Fig. 19; Eeeve, Con- 

 chologia Iconica, Vol. XVI, Unio Plate XCII, Fig. 501. 

 Described from Alexandria, Louisiana. 



Unio canadensis Lea. Jour. Acad. Nat. Sci. Phila., 

 Vol. IV, 1859, p. 268, PL XLIV, Fig. 148. Described 

 in 1857, from the St. Lawrence river, at Montreal. 



Unio subovatus Lea, of Reeve, Conchologia Iconica, 

 Vol. XVI, Unio Plate LXXXV, Fig. 456. This is not 

 the true subovatus Lea. 

 Specimens were obtained only in the Saline river, at Ben- 

 ton. The form is very widely distributed, and presents 

 variant features in all its different habitats. Commonly 

 abundant w^herever it occurs at all, when perfect specimens 

 are obtainable it constitutes one of the most beautiful of 

 Uniones. It is the type of a great natural group, which 

 includes Unio ovatus Say, Unio subovatus Lea, Unio capax 

 Green Unio lineaius Lea, and others. Specimens of the last 

 named, from the original locality in Georgia, indicate that it 

 too must pass into the list of synonyms. 



Margaritana complanata Barnes. 



Plate XVI. 



Alasmodonta complanata Barnes, Am. Jour. Science 

 and Arts, 1st series, Vol. VI, p. 278, PI. XIII, Figs. 17a, 

 17b, 1823. 



Symphynota complanata Lea. Trans. Am. Philos. 

 Soc, 1829, Vol. Ill, p. 448. Transferred from Unio. 

 Unio complanatus Lea. So Reeve, Conchologia 

 Iconica, Vol. XVI, Unio Plate L, Fig. 266. 

 This species is rarely found in the St. Francis, at Witts- 

 burg. While it has a wide range it appears to be most abun- 

 dant in western Illinois, in the Mississippi river, and through- 

 out Iowa. The last named State may, indeed, be said to be its 

 metropolis. The figure is made from a young individual 

 taken in the Des Moines river, and is designed to show 

 the characters of the beaks, which are peculiar to this 

 form. 



