NODULARIA IOI5 
in a blunt point below the median line; hinge line strongly 
curved; anterior end rounded, subangulate above; base line 
curved, quite full just behind the middle; dorsal slope ob- 
liquely truncated and having wrinkled, subradial ridges; epi- 
dermis yellowish-green, darker behind ; teeth lamellar ; pseudo- 
cardinals and laterals curved; muscle scars impressed; nacre 
bluish-white. 
Length 50, height 31, diam. 24 mm. 
River Srakeo, Siam. 
Unio dautzenbergi Morier, Jl. de Conch., XX XVII, 1880, p. 
190, pl. vit, fig. 5. 
Nodularia dautgenbergi SIMPSON, Syn., 1900, p. 819. 
Contradens dautzenbergi Haas, Conch. Cab., Unio, 1912, pl. 
21, figs. 6-7. 
A rather solid species distinguished by its coarse, irregular 
sculpture. The hinge line is quite strongly curved; the nacre 
is rather dull. 
NODULARIA SOBOLES (Fischer). 
Shell irregularly rhomboid, inflated in front, wedge-shaped 
behind, solid; beaks rather full and high; anterior end some- 
what truncated; base line curved, full about the middle, in- 
curved between this and the posterior end; hinge line curved 
throughaut; dorsal slope scarcely truncate; posterior ridge 
inclined to be double, ending in a blunt, rounded point or faint 
biangulation at the base of the shell: surface corrugated, the 
ridges often interrupted; epidermis brownish-green; pseudo- 
cardinals not strong ; laterals curved; nacre whitish. 
Length 68, height 39, diam. 32 mm. 
Siam. 
Unio siamensis Moruet, Jl. de Conch., XX XVII, 1889, p. 194, 
plevil, fie. 2: 
Unio soboles Fiscuer, Bull. Soc. d’Aut., 1891, p. 227. 
Nodularia sobolus Stspson, Syn., 1900, p. 819. 
Contradens sobolus Haas, Conch. Cab., Unio, 1912, pl. 21, 
fig. 5. 
First called Unio siamensis by Morlet, but as that name had 
been used by Lea, Fischer changed it to Unio soboles. Closely 
