788 PBOCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii, 



*SowERBY, CoQch. Icon., XVI, 1868, pi. lxxxvi, fig. 459. — * Calkins, Pr. 

 Ottawa Acad. Sci., 1874, p. 45.—* B. H. AVright, Check List, 1888.—* PiETEL, 

 Conch. Sam., Ill, 1890, p. 170. 

 ''Margarita ( Dnio) trigonua Lea, Syn., 1836, p. 18; 1838, p. 17. 



* Margaron ( Unio) trigoniis Lea, Syn., 1852, p. 25; 1870, p. 38. 

 ""Quadrula trigona Baker, Moll. Chicago, Pt. 1, 1898, p. 76, pL xv, fig. 5. 



*Unio undaUis CoNRAD, New F. W. Shells, 1834, p. 72. — * Say, Am. Conch., 

 VI, 1834. 



* Unio triangularis Kuster, Conch. Cab. Unio, 1852, p. 56, pi. xii, fig. 3. 



* Unio 2nlaris Eeeve, Conch. Icon., XVI, 1865, pi. xxvii, fig. 138. 



Entire Mississippi drainage; Ooosa Eiver, Alabama; Michigan and 

 tlie Upper St. Lawrence drainage. 



tQUADRULA OBLIQUA Lamarck. 



* Unio ohliqua Lamarck, An. sans Vert., VI, 1819, p. 72. — ^Ferussac, Guer. Mag., 



1835, p. 28.—* Deshayes, An. sans Vert, 2d ed., 1835, p. 534; 3d ed., II, 1839, 



p. 668. 

 ^Margarita ( Unio) ohliqua Lea, Syn., 1836, p. 20. 

 *Unio ooliquus Hanley, Test. Moll., 1842, p. 186; *Biv. 1843, p. 186, pi. xx, 



fig. 24. — * Catlow and Eeeve, Conch. Noni., 1845, p. 61. — * Kuster, Conch. 



Cab. Unio, 1852, p. 63, pi. xv, fig. 1.—* Conrad, Pr. Ac. Nat. Sci. Phila.,VI, 



1853, p. 253.— *H. and A. Adams, Gen. Eec. Moll., II, 1857, p. 495.— * Calkins, 



Pr. Ottawa Acad. Sci., 1874, p. 44.— *P^tel, Conch. Sam., Ill, 1890, p. 161.— 



* Call, Tr. Ac. Sci. St. Louis, VII, 1895, p. 31, pi. iv. 

 *Margarita ( Unio) ohliquus Lea, Syn., 1838, p. 17. 

 *Margaron ( Unio) ohliquus Lea, Syn., 1852, p. 25; 1870, p. 38. 

 ""Unio nndatus Barnes, Am. Jl. Sci., VI, 1823, p. 121, pi. iv, fig. 4. — ''Hildreth, 



Am.Jl. Sci., XIV, 1828, p. 280.i—* Conrad, Pr. Ac. Nat. Sci. Phila., VI, 1853, 



p. 259. 

 ""Mya undata Eaton, Zool. Text-Book, 1826, p. 219. 

 ""Unio mytiloides Short and Eaton, Transylvania JL, 1831, p. 74. 



* Unio cordatus Conrad, Monog., V, 1836, p. 48, i^l. xxv. — *Kuster, Conch. Cab., 



1852, p. 57, pi. XIII, fig. 1. — *SowERBY, Conch. Icon., XVI, 1868, pi. lxxiii, 

 376.— *B. H. Wright, Check List, 1888. 



Oliio, Cumberland, and Tennessee river systems; west in Illinois to 

 the Mississippi; Claiborne, Alabama. 



t QUADRULA COCCINEA Conrad. 



*Unio coccineus Conrad,^ Monog., Ill, 1836, p. 29, pi. xiii, fig. 1. — Lea, Tr. Am. 

 Phil. Soc, VI, 1838, p. 12, pi. v, fig. 12; *0b8., II, 1838, p. 12, pi. v, fig. 12.- 

 *Troschel, Arch. fur. Naturg., V, 1839, Pt. 2, p. 234.— *Hanley, Test. Moll.. 

 1842, p. 203; *Biv. Shells, 1843, p. 203, pi. xxii, fig. 54.— *Catlow and Eeeve, 



1 This was figured by Hildreth, but the figures of this species and a number of 

 others were left out by the editor. 



2In the Transactions of the American Philosophical Society, VI, 1838, p. 12, pi. v, 

 fig. 12, Lea described this species, and stated that about eighteen months previous Dr. 

 Hildreth had sent him a single specimen under the name Unio coccineus; but there is 

 nothing to show that Hildreth had described it. In the Monography in 1836, III, 

 p. 29, pi. XIII, fig. 1, Conrad describes this species under the same name, and also 

 credits it to Hildreth, stating that it was in the collection of the Philadelphia 

 Academy of Natural Sciences under that name. The species must be credited to 

 Conrad, who first described it, though Lea read his description in 1834. 



