PHYSUNIO 1067 



Physunio camhodiknsis (Lea). 



Shell small, scarcely subsolid, irregularly obovate, subinflat- 

 ed ; beaks full and high, somewhat eroded in the only speci- 

 men seen but having zigzag-radial sculpture ; posterior ridge 

 double, ending in a feeble biangulation below the median line ; 

 anterior end narrowed and rounded, slightly angled above; 

 base line lightly curved, full behind the middle ; hinge line 

 curved a little, carried out into a small wing behind; dorsal 

 slope oblicjuely truncate ; surface with irregular growth lines, 

 somewhat wrinl-ded on the dorsal slope ; epidermis bronzy-red- 

 dish, shining ; teeth compressed ; laterals curved ; muscle scars 

 shallow; nacre bluish-white, iridescent. 



Length 25, height 15, diam. 11.5 mm. 



Takrong River at Korat, Cambodia. 

 Unio camhodiensis Le;a, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 



103; Jl. Acad. N. Sci. Phil., Ill, 1857, p. 313, pi. xxx, fig. 



28; Obs., VI, 1857, p. 33, pi. XXX, fig. 28. 

 Mar gar on (Unio) camhodiensis Lea, Syn., 1870, p. 42. 

 Physunio camhodiensis Simpson, Syn., 1900, p. 831. — Haas, 



Conch. Cab., Unio, 1912, pi. 34, fig. 5. 



I am not at all sure that the type, the only shell of this spe- 

 cies I have seen, is adult. It is, however, somewhat strong, 

 and the epidermis is of a peculiar bronzy-reddish tint. 



Section Lens Simpson, 1900. 



Lens Simpson, Syn., 1900, p. 831. 



Shell sublenticular ; three laterals oi left valve distinct ; cav- 

 ity of the beaks compressed. 



Type, Unio e.vimins Lea. 



Physunto eximius (Lea). 



Shell subtriangular, compressed, winged on the post-dorsal 

 border, rather thin, inequilateral ; anterior end much narrow- 

 ed, rounded, slightly angled above; base line straight or a lit- 

 tle incurved, full behind the middle ; dorsal outline lightly 

 curved ; dorsal slope almost squarely truncate behind, the line 

 of truncation sometimes a little incurved ; beaks neither full 



