1232 DIPLODON 



ed ; cardinal teeth rather stout, trifid in the left valve ; laterals 

 moderate, somewhat curved ; nacre white. 



Length 52, heig-ht 31, diam. 16.5 mm." (Kuster). 



Type locality, "Rio Conigo, near New Freiberg, Brazil." 

 Unio expansns Kuste:jj. Conch. Cab. Unio, 1856, p. 149, pi. 



XLTIT, fig. 5. 



Diplodon expansns Sampson, Syn., 1900, p. 874. 



I know nothing of this. It looks more like an Australian 

 than a South American form, and is quite likely a D. australis. 



DiPT.ODON PKCUi.iARis (Lea). 



'"Shell smooth, quadrate, somewhat compressed at the sides 

 and inflated on the umbonal slope ; inequilateral, obtusely an- 

 gular behind, rounded before ; substance of the shell some- 

 what thick, slightly thicker before; beaks a little prominent, 

 slightly inflated with divergent folds at the tips ; ligament 

 small and very dark ; epidermis greenish-brown, without rays 

 and with very indistinct lines of growth ; umbonal slope in- 

 flated and rounded ; posterior slope narrow, elliptical, with an 

 indistinct impressed line in each valve ; anterior cicatrices con- 

 fluent, rather small and slightly impressed ; posterior cicatrices 

 confluent, large and very slightly impressed ; dorsal cicatrices 

 in a row across the centre of the cavity of the beaks ; cavity 

 of the shell shallow and wide ; cavity of the beaks very shal- 

 low and rounded ; uacre bluish- white and iridescent. 



Length 2, height 1.3, diam. .9 in." (Lea). 



Paraguay. 

 Unio peculiaris Lka^ Pr. Ac. N. Sci. Phila., X, 1866, p. ;^^ ; 



Jl. Acad. N. Sci. Phila., VL 1868, p. 265. pi. xxxiv, fig. 80 : 



Obs., Xn, 1869, P- 25, pi. XXXIV, fig. 80. 

 Margaron (Unio) peculiaris Lea, Syn., 1870. p. 47. 

 Diplodon peculiaris Simpson, Syn., 1900, p. 874. 

 Unio paragiiayensis Lp;^, Pr. Ac. N. Sci. Phila., X, 1866, p. 



34; Jl. Ac. N. Sci. Phila., VL t868, p. 271, pi. xxxv, fig. 85 ; 



Obs., XIL 1869, p. 31, pi. XXXV. fig. 85. 

 Margaron (Unio) paragnayensis Lea, Syn., 1870, p. 45. 

 f Unio nitidulus Kuster, Conch. Cab. L"''nio., 1848, p. 226, pi. 



I.XXVT, fig. 6. 



