﻿LAMPSIUS 137 



one above it, with one lateral ; beak cavities not deep ; muscle 

 scars shallow ; nacre bluish-white, slightly iridescent behind. 

 Male shell sometimes sub-rhomboid, occasionally bluntly point- 

 ed behind about midway up from the base, often nearly evenly 

 rounded posteriorly ; female shell very slightly inflated at the 

 post-basal part and evenly rounded behind. 



Length (male) 82, height 45, diam. 32 mm. 



Length (female) 74, height 43, diam. 27 mm. 



Ogeechee River, Georgia, west to Jackson, Mississippi. 



Type locality, Black Warrior River, south of Blount Springs, 

 Ala. 

 Unio z'ibex Conrad, New F. W. Shells, 1834, p. 31, pi. 



IV, fig. 3; p. y2. — Chenu, Bib. Conch., ist sen. III, 1845, p. 



17, pi. Ill, fig. 6. 

 Ma/rgarita (Unio) inhex Lra, Syn., 1836, p. 27; 1838, p. 20. 

 Margaron (Unio) vibex Lea, Syn., 1852, p. 30; 1870, p. 48. 

 Lanipsilis vibex Simpson, Syn., icpo, p. 559. 

 Burynia (Micromya) znbex Ortmann, Ann. Car. Mus., VIH, 



19^2, p. 340. 

 Unio exiguus Lea, Pr. Am.. Phil. Soc, I, 1840, p. 287. — Tr. 



Am. Phil. Soc, VIII, 1842, p. 191, pi. VII, fig. I ; Obs., Ill, 



1842, p. 29, pi. VII, fig. I. — Chenu. 111. Conch., 1858, pi. xxx, 



figs. I, la, lb. — SowERBY, Conch. Icon., XVI, 1866, pi. 



XXXVIII, fig. 208. 

 Margaron (Unio) exiguus Lea, Syn., 1852, p. 27; 1870, p. 43. 

 Unio stagnalis Conrad, Ann. and Mag. N. Hist., IV, 1849, p. 



300; Jl. Ac. N. Sci. Phila., I, 1850, p. 275, pi. xxxvii, fig. 2. 

 Margaron (Unio) stagnalis Lea, Syn., 1852, p. 27: 1870, p. 42. 

 Unio rutUans Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 262 ; 



Jl. Ac. N. Sci. Phila., IV, 1858, p. 59, pi. ix, fig. 41 ; Obs., 



VI, 1858, p. 59, pi. IX, fig. 41. — KusTER, Conch. Cab. Unio, 



1861, p. 258, pi. LXXXVII, fig. 3. 

 Margaron (Unio) rutilans Liv\, Syn., 1870, p. 45. 

 Unio subcUipsis Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 262 : 



Jl. Ac. N. Sci. Phila., IV, 1858, p. 62, pi. x, fig. 44 : Obs., VI, 



1858, p. 62, pi. X, fig. 44. 

 Margaron (Unio) subellipsis Lea, Syn., 1870, p. 45. 



