NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSOm 605 



*Plagiola elegans Baker, Moll. Chicago, Pt. 1, 1898, p. 91, pi. xxi, fig. 1. 



Unio truncatus Say, Am. Conch., VI, 1834. — * Ferussac, Guer. Mag., 1835, p. 27. — 



*■ Conrad, Am. Conch, (continuation), Pt. 7, pi. lxvii (no date) ; *" Pr. Ac. 



N. Sci. Phila., VI, 1853, p. 259.— * Kuster, Conch. Cab., 1861, p. 174, pi. lv, 



figs. 2, 3. 



* Unio irmicatus Eafinesque var. elegans. * Pjetel, Conch. Sam., Ill, 1890, p. 170. 



Mississippi drainage generally; Micliiganj Lake Michigan; south- 

 west to Trinity Eiver, Texas. 



(Group of Plagiola donaciformis.) 



Shell small, elongated, triangular oval; posterior ridge generally well 

 defined but rarely sharp, having broken green rays which form chev- 

 rons or blotches on a lighter ground; female shell somewhat inflated 

 in the post-basal region. 



t PLAGIOLA DONACIFORMIS Lea. 



* Unio donaciformis Lea, Tr. Am. Phil. Soc, III, 1828, p. 267, pi. iv, fig. 3 ; * Obs., I, 



1834, p. 9, pi. IV, fig. 3. — * Ferussac, Guer. Mag., 1835, p. 27. — * Deshayes, An. 

 sans Vert. 2d ed.,VI, 1835, p. 547; 3d ed., II, 1839, p. 672.— * Hanley, Test. 

 Moll., 1842, p. 183; *Biv. Shells, 1843, p. 183, pi. xxii, fig. 41.— * Catlow and 

 Reeve, 1845, p. 58.— *Chenu, 111. Conch., 1858, pi. xi, figs.4, 4a,4&.— *B. H. 

 Wright, Check List, 1888. 



* Margarita ( Unio) donaciformis Lea, Syn., 1836, j). 18; 1838, p. 16. 

 *Margaron (Unio) donaciformis Lea, Syn., 1852, p. 24; 1870, p. 36. 



* Plagiola donaciformis Baker, Moll. Chicago, Pt. 1, 1898, p. 92, pi. xiii, fig. 4. 



* Unio zigzag Lea, Tr. Am. Phil. Soc, III, 1829, p. 440, pi. xii, fig. 19 ; * Obs., 1, 1834, 



p. 54, pi. XII, fig. 19. — Short and Eaton, Transylvania Jl., 1831, p. 79. — 



* Deshayes, An. sans Vert. 2d ed., VI, 1835, p. 551; 3d ed., II, 1839, p. 673.— 



* Hanley, Test. Moll., 1842, p. 183 ; * Biv. Shells, 1843, p. 183, pi. xxii, fig. 42.— 



* Catlow and Eeeve, Conch. Nom., 1845, p. 65. — * Kustek, Conch. Cab. Unio, 

 1852, p. 42, pi. VIII, fig. 3.— H. and A.Adams, Gen.Rec. Moll., 1857, p. 495.— 

 *Chenu, 111. Conch., 1858, pi. viii, figs. 8, 8a, 8&; Man., 1859, II, p. 138, fig. 

 670.—* SowERBY, Conch. Icon., XVI, 1866, pi. xxxix, fig. 213.—* Calkins, Pr. 

 Ottawa Ac. Sci., 1874, p.46.— *B. H. Wright, Check List, 1888.— * P.etel, 

 Conch. Sam., Ill, 1890, p. 172. 



* Margarita {Unio) zigzag Lea, Syn., 1836, p. 18; 1838, p. 16. 

 * Ma7-garon {Unio) zigzag Lea, Syn., 1852, p. 24; 1870, p. 36. 



* Unio nervosa Conrad, New F. W. Shells, 1834, p. 70. 



* Unio nervosHs Say, Am. Conch., VI, 1834.—* Ferussac, Guer. Mag., 18.35, p. 27. — 



* Conrad, Pr. Ac. N. Sci. Phila., VI, 1853, p. 253.—* Kuster, Conch. Cab. 

 Unio, 1861, p. 175, pi. lv, fig. 4. 



Mississippi drainage generally; Alabama Eiver area; southwest to 

 the Trinity Kiver, Texas ; Michigan. Seems to be gradually replaced 

 in the southwest by P. macrodon, and there are specimens which can 

 scarcely be assigned with certainty to either species. 



t PLAGIOLA MACRODON Lea. 



* Unio macrodon Lea, Pr. Ac. N. Sci. Phila., Ill, 1859, p. 154 ; * Jl. Ac. N. Sci. Phila., 



VI, 1862, p. 193, pi. XXVI, fig. 262; *Obs., IX, 1863, p. 15, pLxxvi, fig. 262.— 



* ? Sowerby, Conch. Icon., XVI, 1868, pi. lxxxviii, fig. 437.—* B. H. Wright, 

 Check List, 1888.— *P.etel, Couch. Sam., Ill, 1890, p. 158. 



*Margaron { Unio) macrodon Lea, Syn. 1870, p. 37. 



Eastern Texas, northward probably into Kansas. 



