55° UNIO 
Unio terminalis Bourcuicnat, Test. Noviss., 1852, p. 31; Cat. 
Rais. Moll. 1853, p. 76, pl. ws, figs. 4-6; Jl. de Conch., IV, 
1853, p: 74, pl. 11, figs. 10’ 10”.—Kopentlcon., TV, 1876: 
p. 65, pl. cxrx, fig. 115.—SIMPSON, Syn., 1900, p. 689. 
Margaron (Unio) terminalis Lra, Syn., 1870, p. 39. 
This species is almost evenly long elliptical, being just a 
little more rounded on the dorsal than the ventral outline. 
The beaks are slightly nearer the anterior end than in the 
nearly allied U. pietri and it is not angled at the upper anterior 
part. ‘This species has the post-dorsal slope wrinkled and in 
pretri there are occasionally traces of folds in this region. 
UNIO GRELLOISIANUS Bourguignat. 
Shell solid, nearly regularly ovate, inequilateral, inflated or 
subinflated ; beaks somewhat full and elevated, their sculpture 
consisting of numerous subconcentric ridges that have a ten- 
dency to wear into nodules; posterior ridge subangular, placed 
near the dorsal line, ending behind in a decided point a little 
below the median line: surface finely, concentrically striate ; 
epidermis yellowish-fulvous ; pseudocardinals subcompressed ; 
laterals slightly curved; anterior muscle scars deep; posterior 
scars triangular. 
Length 30, height 18, diam. 15 mm. 
length 60, height 35, diam. 22 mm. 
Jordan River. 
Unio grelloisianus Bourcuicnar, Rev. et Mag., VIL, 1856, p. 
227, pl. x1, figs. I-4.— SIMPSON, Syn., 1900, p. 689.—KoseELt, 
Icon., new ed., XVIII, 1912, p. 58, pl. pvr, fig. 2676. 
Unio lunulifer Bourcuicnat, Rev. et Mag., VIII, 1856, p. 227, 
pl. xr. figs. 5-8.—Kopetr, Icon., new ed., XVIII, 1912, p. 
57, pl. pviti, fig. 2674. 
Margaron (Unio) lunulifer Lea, Syn., 1870, p. 37. 
Unio jordanicus Bourcutcnat, Rev. et Mag., VII, 1856, p. 
228, pl. x, figs. 1-4.—Korew, Icon., new ed., X Vil, 19r2)-p. 
56, pl. pvitt, fig. 2672. 
Margaron (Unio) jordanicus Lea, Syn., 1870, p. 44- 
