﻿442 GABirj.OTiA 



or below the median line; posterior ridge low, ending- in a 

 blunt, rounded point at the posterior base of the shell ; liga- 

 ment long ; surfaee eoneentrieally striate ; epidemiis dark horn- 

 colored or brown ; hinge strong, each valve having a well-de- 

 veloped, triangular, compressed tooth ; nacre orange-tinted. 



Length 120, height 80, diam. 40 mm. 



Euphrates River. 

 Unio oppcrti Ijoukguignat, Rev. et Mag., \'1II, 1856, p. 71, 



pis. \in, fig. 6; IX, fig. i. 



Pscudodon oppcrti Wkstkui.und, Faun. Pal., II, Pt. 7, 1890, 



p. 182. 

 Margantana oppcrti P.ijTEi,, Conch. Sam., Ill, 1890, p. 173. 

 Gahillotia oppcrti Simpson, Syn., 1900, p. 650. 

 Pseudodontopsls oppcrti Kop.elt, Icon., new ed., XIX, 1912, 



p. 6, pi. Dxiv, fig. 2692. 



Only a single valve of this fine species was obtained by Op- 

 pert, but there are two shells in the Lea collection that I refer 

 to this species. It diflfers from G. pscudodopsis in having the 

 whole dorsal outline much more strongly curved than that of 

 the base, in fact the line of the hinder part of the base is 

 straight. 



Gabilliotia kupiiratica (Bourguignat). 



Shell subrhomboid, compressed, scarcely subsolid, inequi- 

 lateral ; beaks low, compressed ; posterior ridge low, double, 

 ending behind a little below the median line in a wide, faint 

 biangulation ; post-dorsal region elevated into a low wing, 

 which is truncated behind ; base rounded ; anterior end nar- 

 rowed, rounded and slightly cut away below ; surface finely 

 concentrically striate, shining, fuscous-green ; hinge with a 

 single imperfect, compressed, smooth tooth in each valve, that 

 in the left under the beak, that in the right a little in front of 

 it : muscle scars shallow ; nacre white, tinted puri>le, silvery. 



Length 70, height 53, diam. 20 mm. 



Asiatic Turkey. 

 Unio cnphratiais Rourguionat, Test. Nov., 1852. ]i. 28 ; Cat. 



Rais., 1853. p. 75, pi. IV. figs. 1-3. 



