tae 
£ 
| PROCEEDINGS OF THE NATIONAL MUSEUM. 431 
in color and peculiar texture. The single specimen from which he de- 
scribed the species was badly eroded and in poor condition, and is not 
in his collection, nor do I know where itis. I have specimens of U. 
anodontoides before me from various localities in southern Mississippi, 
Alabama, and Georgia, and the Withlacoochee River in Florida, col- 
lected by Johnson and Rugel. and by the latter from Simpson Creek, 
Florida. 
GROUP OF UNIO NASUTUS. 
Wide shells, of rather light structure; undulate beaks, and usually 
dark greenish, somewhat rayed, epidermis, with lurid purple, silvery, or 
bluish, often iridescent nacre. The posterior end is usually drawn out 
to a point; is sometimes more or less ridged and biangulate. U. nasu- 
tus, the type, is abundant on the Atlantic slope from Canada to south- 
ern Virginia, and is also found west to Illinois. 
Unio aheneus Lea. 
(Plate Lxx1, Fig. 6.) 
Unio aheneus Lea, Obs. Iv, p. 38, Pl. xii, Fig. 9, Aug. 18, 1843. Black Cr., Fla.; 
S. B. Buckley. 
Lea’s type is a young specimen not over half grown. The epidermis 
is green and yellow, neatly rayed; the shell is compressed, very wide, 
rather narrow posteriorly, and somewhat widened behind, either bian- 
gulate or, in some specimens, ending in a single produced point. The 
nacre is usually lurid and coppery shaded, but specimens belonging to 
Rev. A. Dean, of Muncy, Pa., from Lake Ashby, are blackish almost 
without rays, and have dark purple nacre. 
Unio Waltoni B. H. Wright. 
(Plate Lxxit, Fig. 7.) 
Unio Waltoni B. H. Wright, Proc. Acad. Nat. Sci. Phila., 1888, p. 144, Pl. u, Fig. 3, 
Lake Woodruff, Volusia Co. 
This species is close to the last, as it is to several other members of 
the group. It is, however, a wider, larger species than U. aheneus; is 
more produced in the ventral region; has a rougher, darker epidermis; 
‘is slightly less solid, and has commonly a rather sharp point just in 
front of the beaks. It is probable that it may be found to connect with 
aheneus. 
GROUP OF UNIO GIBBOSUS. 
Wide, solid shells, with usually rough epidermis, varying from yellow- 
ish and green—in some species rayed or tesselated—to dark brown, 
Hinge plate heavy; teeth strong, the laterals well elevated and ending 
abruptly behind... Nacre varying from white, through salmon, to deep 
purple, variable in color often in the same species. There are in almost 
all the examples of the group one or more shallow furrows or depres- 
sions within, running from near the cardinals in a direction more or less 
