718 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



tUNIO ARCTATUS var. TORTIVUS Lea. 



* t Unto tortivus Lea,i Pr. Am. Phil. Soc, 1, 1840,p. 287 ; Tr. Am. Phil. Soc.,VIII, 1842, 



p. 204, pi. XII, tig. 17 ; Obs., Ill, 1842, p. 42, pi. xii, fig. 17.— "Conrad, Pr. Ac. N. 

 Sci. Phila.,VI, 1853, p. 2.59.— H. and A. Adams, Gen. Rec.MolL, II, 1857,p.493.— 

 * Chenu, 111. Conch., 1858, pi. xxix, figs. 6, 6a, 66. — " Sowerby, Conch. Icon., 

 XVI, 1866, pi. XXXVI, fig. 193.—* B, H. Wright, Check List, 1888.— * Pjstel, 

 Conch. Sam., Ill, 1890, p. 169.— * Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 

 421, pi. LXiii, fig. 8; LXiv, figs. 1, 3, 4. 



*Margaron ( Uiiio) tortivus Lea, Syn., 1852, p. 33; 1870, p. 53. 



*\Umo tetricus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 170; *J1. Ac. N. Sci. Phila., 

 IV, 1859, p. 195, pL XXII, fig. 78: * Obs., VII, 1859, p. 13, pi. xxii, fig. 78.— 

 TRUSTER, Conch. Cab. Unio, 1862, p. 276, pi. xci, fig. 7; xciii, fig. 3.— *B, H. 

 Wright, Check List, 1888.— * P/etel, Conch. Sam., Ill, 1890, p. 169. 



*Margaron ( Unio) tetricus Lea, Syn., 1870, p. 53. 



"Wnio purpurellus Lea,* Pr. Ac. N. Sci. Phila., IX, 1857, p. 171; *J1. Ac. N. Sci. 

 Phila., IV, 1859, p. 19, pi. xxiii, fig. 81; *Obs., VII, 1859, p. 16, pi. xxiii, 

 fig. 81.— ^B. H. Wright, Check List, 1888. 



* Margaron {Unio) purpurellus Lea, Syn., 1870, p. 53. 



*t Unio merceri Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 169; *J1. Ac. N. Sci. 

 Phila., V, 1862, p. 209, pi. xxxi, fig. 278; *Obs., IX, 1863, p. 31, pi. xxxi, 

 fig. 278.— *B. H.Wright, Check List, 1888.— *PiETEL, Conch. Sam., Ill, 

 1890, p. 159. 



* Margaron ( Unio) merceri Lea, Syn., 1870, p. 61. 



Florida 5 South Georgia; tbe type west to the Black Warrior Eiver, 

 Alabama. 



tUNIO NIGELLUS Lea. 



" Unio nigellus Lea, Pr. Am. Phil. Soc, V, 1852, p. 251 ; * Tr. Am. Phil. Soc, X, 1852, 

 p. 283, pi. XXIV, fig. 42; *Obs., V, 1852, p. 39, pi. xxiv, fig. 42.— * Conrad, Pr. 

 Ac. N. Sci. Phila., VI, 1853, p. 253.— *H. and A. Adams, Gen. Eec Moll,, II, 

 1857, p. 494.— *B. H.Wright, Check List, 1888.— *P^tel, Conch. Sam., 

 Ill, 1890, p. 161. 



* Margaron {Unio) nigellus Lea, Syn., 1852, p. 30; 1870, p. 53. 



*t Unio denigratus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 171; *J1. Ac. N. Sci. 

 Phila., IV, 1859, p. 200, pi. xxiii, fig. 83; *Obs., VII, 1859, p. 18, pi. xxiii, 

 fig. 83.— 'B. H. Wright, Check List, 1888.— * Simpson, Pr. U. S. Nat. Mus., 

 XV, 1892, p. 422, pi. lxv, fig. 1. 



*Margaron {Unio) denigratus Lea, Syn., 1870, p. 52. 



Chattahoochee River system: south into Florida. 



t UNIO PINEI B. H. Wright. 



*Z7nio pinei B. H. Wright, Naut., XI, 1897, p. 40.— * Simpson, Pr. Ac. N. Sci. 

 Phila., 1900, p. 80, pi. in, fig. 1. 



North Florida. 



' Unio arctatus is a widely distributed, abundant, and variable species, ranging 

 from the Black Warrior River to southern Florida. I have examined a great amount 

 of material from the Black Warrior aud Cahavrba rivers (collected by Call), from 

 the Flint and Chattahoochee rivers from the Lea and other collections, and I feel 

 reasonably sure that all the species I have united should go together. 



'^I believe this to be a small, somewhat inflated form of arctatus. 



