662 PROCEEDINGS OF THE \.lTloy.lL MUSEUM. 



tARCIDENS CONFRAGOSUS Say. 



*Alasmodonta confragosa SAY, N. Harm. Diss., II, 1829, p. 339 ; * Am. Conch., I, 1830, 

 pi. xxi; IV, 1832 (cover p. 4). *CONHAI>, New F. W. Shells, 1834, p. 72. 

 TERUSSAC.Gner. Mag., 1835, p. 26. "CiiEXU, Bib. Conch., 1st ser., Ill, 1845, 

 p. 30, pi. vin, figs. 1, la. *COXRAD, Pr. Ac. Nat. Sci. Phila., VI, 1853, p. 262. 



"Margarita (Margarilana) confragosa LEA, Syii., 1836, p. 43; 1838, p. '21. 



"Unio confragosa DESHAYES, An. sans Vert., 2d ed., VI, 1835, p. 552; 3d ed., II, 

 1837, p. 674.* HANLEY, Test. Atoll., 1842, p. 210; v Biv. Shells, 1843. p. 210. pi. 

 xxiii, fig. 52. * DESHAYES, Tr. Elem., 1853, p. 217, pi. xxx, tigs. 5-7. 



*Baplna confragosa II. and A. ADAMS, Gen. Kec. Moll., II, 1857, p. 500. 



*Margaron (Margaritana) confragosa LEA, Syn., 1852, p. 42; 1870, p. 67. 



* Margaritana confragosa CALKINS, Pr. Ottawa Acad., 1874, p. 46. * B. H. WRIGHT, 



Check List, 1888. * PJSTKI., Conch. Sam., Ill, 1890, p. 172. 



*Unio confragosus CATLOW and REEVE, Conch. Nona., 1845, p. 57. *SO\VERBY, 

 Couch. Icon., XVI, 1867, pi. LX, fig. 299. 



Mississippi Eiver and States adjoining it; Ohio liiver drainage; 

 southwest to the Colorado River, Texas. A specimen is in the Lea 

 collection, said to be from Enterprise, southeastern Alabama, but I 

 am doubtful about the locality. 



Genus SYMPHYNOTA Lea, 1829. 

 (Type, Symphynota compressa LEA.) 



Symphynota LEA, Tr. Am. Phil. Soc., Ill, 1829, p. 424. 

 ^Megadomns SWAIXSON, Tr. on Mai., 1840, p. 266. 

 ? Complanaria SWAINSON, Tr. on Mai., 1840, p. 290. 



Shell elliptic rhomboid, compressed ; beaks low, their sculpture con- 

 sisting of strong bars; one pseudocardinal in the right valve and two 

 in the left, the hinder somewhat A-shaped, cutting off the hinge plate 

 in the right valve; laterals generally imperfect. 



Animal with the gills semicircular below, inner ^the larger, free nearly 

 the whole length from the abdominal sac; marsupium thick, padlike, 

 filling the outer gills; mantle strongly attached at palleal line; branchial 

 opening papillose; anal opening Avithout papilla 1 . 



Subgenus SYMPHYNOTA Lea, 1829. 



Shell smooth, subsolid, shiniug, rayed; teeth delicate; laterals com- 

 pressed, moderately developed. 



SYMPHYNOTA COMPRESSA Lea. 



* Sympliynota compressa LEA, Tr. Am. Phil. Soc., 1829, p. 450, pi. xn, fig. 22; * Obs., 



I, 1834, p. 64, pi. xn, fig. 22.* FERUSSAC, Guer. Mag, 1835, p. 25. 



* Complanaria compressa CONRAD, Pr. Ac. Nat. Sci. Fhila., VI, 1853, p. 261. 



* Microcondylaea compressa P/ETEL, Conch. Sam., Ill, 1890, p. 175. 



* Unio compressus CONRAD, New F. W. Shells, 1834, p. 68 ; * Monog., VIII, 1837, p. 71, 



pi. XL, fig. 1. *C. B. ADAMS, Thompson's Hist.Vt., 1842, p. 166. * HANLEY, 

 Test. Moll., 1842, p. 174; *Biv. Shells, 1843, p. 174, pi. xx, fig. 39.* DE KAY, 

 Zool. of N. Y.,Pt. 5, 1843, p. 191, pi. xxi, fig. 245. * CATLOW and REEVE, 

 Conch. Norn., 1845, p. 57. *KUSTER, Conch. Cab. Unio, 1861, p. 198, pi. 

 LXIV, figs. 3, 4.* SOWERBY, Couch. Icon., XVI, 1868, pi. LXI, fig. 303. 



