874 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



tDIPLODON AMPULLACEUS Lea. 



*■ Unio ampullaceus Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 34 ; * Jl. Ac. N. Sci. Phila,, 



VI, 1868, p. 269, pi. XXXV, fig. 83; '■ Obs., XII, 1869, p. 29, pi. xxxv, fig. 83. 

 ^ Margaron ( Unio) ampullaceus Lea, Syn., 1870, p. 53. 



South America. 



tDIPLODON APPRIMUS Lea. 



'' Unio apprimus Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 34; * Jl. Ac. N, Sci. Phila., 

 VI, 1868, p. 263, pi. XXXIII, fig. 78; Obs., XII, 1869, p. 23, pi. xxxiii, fig. 78. 



* Margaron ( Unio) apprimus Lea, Syn., 1870, p. 46. 



South America. 



tDIPLODON WYMANII Lea.' 



* Unio unjmanii Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 90; * Jl. Ac. N. Sci. Phila., 



VI, 1863, p. 381, pi. XLii, fig. 289; * Obs., X, 1863, p. 17, pi. XLii, fig. 289.— 

 *SowERBY, Conch. Icon., XVI, 1868, pi. Lxxxiv, fig. 449.— * von Martens, 

 Mai. Bl., XV, 1868, p. 193.—* PiETEL, Conch. Sam., Ill, 1890, p. 172. 

 "" Margaron {Unio) ivymanii, Lea, Syn., 1870, p. 35. 



Uruguay Kiver, South America. 



- DIPLODON EXPANSUS Kuster.^ 



* Unio expansus Kustek, Conch. Cab. Unio, 1856, p. 149, pi. xliii, fig. 5. — * P^tel, 



Conch. Sam., Ill, 1890, p. 152. 



Brazil 1 



tDIPLODON PECULIARIS Lea. 



* Unio peculiaris Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 33; * Jl. Acad. N. Sci. Phila., 



VI, 1868, p. 265, pi. xxxiv, fig. 80; Obs., XII, 1869, p. 25, pi. xxxiv, fig. 80. 

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



* \Unio paraguayensis Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 34; *J1. Ac. N. Sci. 



Phila., VI, 1868, p. 271, pi. xxxv, fig. 85 ; Obs., XII, 1869, p. 31, pi. xxxv, fig. 

 85.— ^ VON Martens, S. B. Nat. Fr., 1895, p. 34. 



* Margaron ( Unio) paraguayensis Lea, Syn., 1870, p. 45. 



"^Unio nitidulus KusTER, Conch. Cab. Unio., 1848, p. 226, pi. Lxxvi, fig. 6.— 

 * PIETEL, Conch. Sam., Ill, 1890, p. 161. 



Paraguay. 



tDIPLODON FIRMUS Lea.s 



* Uniofirmus Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 33; *J]. Ac„. N. Sci. Phila., VI, 



1868, p. 267, pi. xxxiv, fig. 82; ^Obs., XII, 1869, p. 27, pi. xxxiv, fig. 82. 



* Margaron. ( Unio) Jirmus Lea, Syn., 1870, p. 45. 



DIPLODON FIRMUS var. BCETTGERI von Ihering. 



*Unio Jirmus Lea var. boettgeri von Ihering, Arch, fiir Nat., 1893, p. 105, pi. iv, 

 fig. 2.—* Nehring, Jl. de Conch., 1894, p. 83. 



Brazil. 



' Extremely close to ajyprlmus, and probably only a young shell of that species. 



'^I know nothing of this. It looks more like an Australian than a South American 

 form, and is quite likely a D. australis. Kuster credits it to Charpeutier manu- 

 script. 



■'•A little longer and more solid than peculiaris, but 1 doubt whether it is distinct. 

 The types of these two ^nd paraguayensis are badly worn. 



