NO. 1205. SYNOPSIS OF THE NATADES SIMPSON. 517 



Subgenus TEUNCILLA Rafinesque, 1819. 



Shell covered with broken rays, somewhat triangular, and without a 

 wide, radiate, posterior furrow. 



(Group of Truncilla Iriquetra.) 



Shell greatly inflated, sharply truncate posteriorly; inflation of the 

 female shell at extreme post-basal point. 



' t TRUNCILLA TRIQUETRA Rafinesque. 



2 * Truncilla iriqueter RAFINESQUE, Ann. Gen. Sci. Phys. Brnx., XIII, 1820, p. 300, pi. 



LXXXI, figs. 1-4. *CHENU, Bib. Conch., 1st ser., Ill, 1845, p. 15, pi. II, lig. 



1. *AGASSIZ, Arch. fiir. Naturg., I, 1852, p. 44. 

 Unto triqtteter SHORT and EATON, Transylvania Jl., 1831, p. 79. *SAY, Am. 



Conch., VI, 1834.* CONRAD, New F.W. Shells, 1834, p. 72.* FERUSSAC, Guer. 



M:ig., 1835, p. 27.* SAY, Pr. Ac. N. Sci. Phila., VI, 1853, p. 259.* H. and A. 



ADAMS, Gen. Rec. Moll., II, 1857, p. 496. * P/ETEL, Conch. Sam., Ill, 1890, 



p. 170. 



* Unio trianyitlaris BARNES, Am. Jl. Sci., VI, 1823, p. 272, pi. xni, fig. 17. *HiL- 



DRKTII, Am. Jl. Sci., X, 1828, p. 287, fig. * SAY, Am. Conch., No. 1, 1830, pi. 

 iv. SHORT and EATON, Transylvania JL, 1831, p. 78. * DESHAYES, An. sans 

 Vert., 2d ed., VI, 1835, p. 554 ; 3d ed., II, 1839, p. 674. * REEVE, Conch. Syst., I, 

 1841, p. 118, pi. LXXXIX, fig. 9. *HAXLKY, Test. Moll., 1842, p. 183 ; *Biv. Shells, 

 1843, p. 183. * CATLOW and REEVE, Conch. Nom., 1845, p. 64. * CHENU, Bib. 

 Conch., 1st ser., Ill, 1845, p. 10, pi. \, figs. 4, 4&; *Man., II, 1859, p. 137, fig. 

 062. *SOWERBY, Conch. Icon., XVI, 1868, pi. LXVII, tig. 340. * CALKINS. Pr. 

 Ottawa Acad. Nat. Sci., 1874, p. 45. 

 *Mya iriangularis EATOX, Zool. Text Book, 1826, p. 221. 



* Margarita ( Unio) triangularis LEA, Syn., 1836, p. 18; 1838, p. 16. 

 *Margaron (Unio) trianyularis LEA, Syn., 1852, p. 23; 1870, p. 36. 

 *Unio cunedtus SWAINSON, Phil. Mag., 1823, p. 112. 



* Unioformosu8 LEA, Trans. Am. Phil. Soc., IV, 1834, p. Ill, pi. xvi, fig. 41 ; * Obs. I, 



1834, p. 121, pi. xvi, fig. 41. *CHENU, 111. Couch., 1858, pi. vm, figs. 12, 12a, 

 12ft ; * Man., 1859, II, p. 138, fig. 664. 



Ohio River drainage; western New York to southern Michigan; 

 Iowa; eastern Nebraska to Indian Territory. 



(Group of Truncilla brevidens.) 



Shell somewhat quadrate, not sharply truncate behind; post-basal 

 swelling of female in front of post-basal point and rounded below. 



t TRUNCILLA BREVIDENS Lea. 



Unio brevidens LEA, Trans. Am. Phil. Soc., IV, 1834, p. 75, pi. iv, fig. 6; *Obs. I, 

 1834, p. 85, pi. vi, fig. 6.* HAXLEY, Test. Moll., 1842, p. 198 ; * Biv. Shells, 1843, 

 p. 198, pi. xx, fig. 41. * CATLOW and REEVE, Conch. Norn., 1845, p. 56. 

 *H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 492. * CHENU. 111., Conch., 

 1858, pi. vm, figs, 6, 6a, 66. *P^TEL, Conch. Sam., Ill, 1890, p. 146. 



* Margarita ( Unio) brevidens LEA, Syn., 1836, p. 29; 1838, p. 21. 

 *Margaron ( Unio) breindens LEA, Syn., 1852, p. 32 ; 1870, p. 50. 



'A t placed before a species indicates that the type, or what are believed to be 

 authentic specimens have been examined by the writer. 

 2 An * in front of a reference indicates that it has been verified. 



