DIPLODON 1303 



below the median line ; surface delicately, concentrically stri- 

 ate ; epidermis pale olive-green, feebly rayed and having a 

 metallic luster, sometimes banded ; teeth very delicate, com- 

 pressed ; pseudocardinals double in the right valve, single in 

 the left ; laterals double in the left valve, single in the right ; 

 nacre bluish-white, iridescent. 



Length 52, height 24.5, diam. 13.5 mm. 

 Australia. 

 Unio xvilsonii Lea. Pr. Ac. N. Sci. Phila.. 1859, p. 153; Jl. Ac. 

 N. Sci. Phila.. IV. i860, p. 257. pi. xl, fig. 137; Obs., VH, 

 p. 74. pi. XL, fig. 137. — SowTiRi'.Y, Conch. Icon., XVI, 1868, 

 pi. Lxxxviii, fig. 474. 

 Margaron (Unio) unlsonii L-'^a, Syn., 1870, p. 47. 

 Diplodon ivilsonii Simpson, Syn., 1900, p. 892. 

 Unio (Alasmodon) stitarti Adams and Axgas, Pr. Zool. Soc. 



Lond., 1863, p. 417. 

 Unio stiiarti Sowerp.v. Conch. Icon.. XVI. 1866, pi. liv, fig. 



279. 

 Anodon sttiarti Sowkrhv, Conch. Icon., XVII, 1867. pi. xxxiv, 



figs. 136, 136a, 136/'. 

 Margaron fUnio) stuarti Lea, Syn., 1870, p. 52. 

 Margaritana stuarti P.T;'rEL, Conch. Sam., Ill, 1890, p. 174. 

 Anodonta stuarti P.TiTEL, Conch. Sam.. III. 1890, p. 185. 



A delicate, somewhat shining species with a slight metallic 

 luster and having compressed, rather feeble teeth. A speci- 

 men from the Stuart Expedition labeled Unio stuarti Adams 

 and Angas. agrees perfectly with Lea's figures and description 

 of U . 7vilsonii and with the description of Adams and Angas 

 of Unio (Alasmodon ) stuarti. and Sowerby's Unio stuarti and 

 Anodon stuarti. The original description states that the shell 

 is plicate posteriorly and one of the National Museum shells 

 shows traces of plication in that region, .\nother specimen 

 whose beaks are somewhat eroded, shows traces of radial 

 sculpture. 



DiPLODON EVANSi (Adams and Angas). 



Shell short, elliptic rhomboid, or subcjuadrate. thin, scarcely 

 inflated or convex, inequilateral ; beaks full and somewhat ele- 

 vated ; posterior ridge rounded ; dorsal outline nearly straight 



