692 UNIO 
Unio nasutulus Lea, Jl. Ac. N. Sct. Phila., VI, 1866, p. 12, pl 
w1, fig. 9; Obs., XI, 1867, p. 16, pl. 11, fig. 9—SIMPson, 
SYN. 1900, p75: 
Margaron (Unio) nasutiulus Lea, Syn., 1870, p. 60. 
The name was originally spelled nasutilus, a typographical 
error, no doubt, and was afterwards changed by Dr. Lea to 
nasutulus. His specimens are small, rather shorter in propor- 
tion than prodiuctus or fisherianus, and in some cases inclined 
to be obovate. 
UNIO FISHERIANUS Lea. 
Shell elongate, compressed or subcompressed, rather thin to 
subsolid, inequilateral, with low beaks, whose sculpture con- 
sists of strong, longitudinal, corrugated ridges; posterior ridge 
well developed, subangular, generally curved down in the mid- 
dle, ending behind in a long drawn-out point about at the 
median line, the point often turned up a little; anterior end 
rounded, wider than the hinder end; surface with decided 
concentric striz; epidermis olive, dirty green, brownish or 
nearly black, often feebly rayed, scarcely shining; pseudocar- 
dinals stumpy, two in the left valve and one, sometimes two, 
in the right: laterals straight; anterior scars impressed ; pos- 
terior scars shallow; nacre whitish or purple-tinted, iridescent 
behind. 
Length 75, height 26, diam. 14 mm. 
Length 76, height 30, diam. 18 mm. 
Length 92, height 35, diam. 18 mm. 
Virginia; Maryland; Pennsylvania, in the Atlantic drainage. 
Type locality, Headwaters of Chester River, Md. 
Unio fisherianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 8, pl. rv, 
fig. 8; Obs., IT, 1838, p. 8, pl. rv, fig. 8—HAnLEy, Biv. Shells, 
1843, p. 206, pl. xxu, fig. 52—CHENU, II]. Conch., 1858, pl. 
XxX, figs. 4, 4a, 4b—KusTeEr, Conch. Cab. Unio., 1861, p. 
205, pl. Lxvimi, fig. 6—RereEve, Conch. Icon., XVI, 1865, pl. 
XXIV, fig. 113.—HaArtmMan and MicHeEener, Conch. Cest., 
1874, p. 90, fig. 187.—Simrson, Syn.,-1900, p. 735. 
Margarita (Unio) fisherianus Les, Syn., 1836, p. 37; 1838, p. 
24. 
