662 PROCEEDINGS OF THE NATIONAL 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).—* Conrad, New F. W. Shells, 1834, p. 72.— 

 *Ferussac, Guer. Mag.,1835, p.26.— "Chexu, Bib. Conch., 1st ser., Ill, 1845, 

 p. 30, pi. VIII, figs. 1, la.—' Conrad, Pr. Ac. Nat. Sci. Phila., VI, 1853, p. 262. 



"Mai-garita (Margaritana) confragosa Lea, Syu., 1836, p. 43; 1838, p. 27. 



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

 1837, p. 674.—* Hanley, Test. Moll., 1842, p. 210; * Biv. Shells, 1843, p. 210, pi. 

 XXIII, fig. 52,— 'Deshayes, Tr. Elem., 1853, p. 217, pi. xxx, figs. 5-7. 



"Baiyhia confragosa II. and A. Adams, Gen. Rec. Moll., II, 1857, p. 500. 



*Margaron {Margaritana) confragosa J^-ea, Syn., 1852, p. 42; 1870, p. 67. 



"" Margaritana confragosa Calkins, Pr. Ottawa Acad., 1874, p. 46. — * B. H. WRit4HT, 

 Check List, 1888.— * P^tel, Conch. Sam., Ill, 1890, p. 172. 



*Unio confragosus Catlow and Reeve, Conch. Nom., 1845, p. 57. — *Sowerby, 

 Conch. Icon., XVI, 1867, pi. lx, fig. 299. 



Mississippi Eiver and States adjoining it; Ohio Eiver drainage; 

 southwest to the Colorado Eiver, 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, Syni2)liynota compressalj'EA.) 



Symphynota Lea, Tr. Am. Phil. Soc, III, 1829, p. 424. 

 IMegadomus Swainson, 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 oft' the hiuge 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; niarsupium thick, padlike, 

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

 opening papillose: anal opening without papilhT. 



Subgenus SYMPHYNOTA Lea, 1829. 



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

 pressed, moderately developed. 



SYMPHYNOTA COMPRESSA Lea. 



"" Symphynota compressa Lea, Tr. Am. Phil. Soc, 1829, p. 450, pi. xii, fig. 22 ; * Ohs., 

 I, 1834, p. 64, pi. XII, fig. 22.— *Ferussac, Guer. Mag, 1835, p. 25. 



* Complanaria compressa Conrad, Pr. Ac. Nat. Sci. Fhila., VI, 1853, y. 261. 



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



* Unio compressHs Conrad, NewF.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. Nom., 1845, p. 57.— *Kuster, Conch, Cab. Unio, 1861, p. 198, pi. 

 LXiv, figs. 3, 4.— *SowERBY, Conch. Icon.jXVI, 1868, pl.LXi, fig. 303. . 



