NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSON. 831 



PHYSUNIO CROSSEI Deshayes and Julien. 



^Unio crossei Deshayes and Julien, N. Arch. Mus., X, 1874, p, 124, pi. vi, figg. 

 5-7._* p.ETEL, Conch. Sam., Ill, 1890, p. 149. 



Cambodia; Cocliiu China. 



t PHYSUNIO MICROPTERUS Morelet. 



* Unio vncroptertis Morelet, Jl. de Conch., XIV, 1866, p. 63; Ser. Conch., IV, 1875, 



p. 349, pi. XV, fig. 7.—" P^ETEL, Couch. Sam., Ill, 1890, p. 158. 



Siam; Cambodia. 



PHYSUNIO SEMIALATUS Deshayes and Julien. 



* Unio semialatus Deshayes and Julien, N. Arch. Mus., X, 1874, p. 123, pi. vi, figs. 



1,2.' 



Siam; Cambodia. 



f PHYSUNIO CAMBODIENSIS Lea.2 



* Unio camhodiensis Lea, 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. 



* Margaron (Unio) camhodiensis Lea, Syn., 1870, p. 42. 



Takrong Eiver at Korat, Cambodia. 



Section LENS Simpson, 1900. 

 (Type, Unioeximius Lea.) 



Shell sublenticular ; three laterals of left valve distinct ; cavity of the 

 beaks compressed. 



t PHYSUNIO EXIMIUS Lea. 



* Unio eximius Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 93; Obs., VI, 1857, 



p. 14, pi. XXV, fig. 8; Jl. Ac. N. Sci. Phila., Ill, 1858, p. 294, pi. xxv, fig. 8.— 

 * VON Martens, Pr. Zool. Soc. Loud., 1860, p. 15. — * Sowerby, Conch, Icon., 

 XVI, 1868, pi. Lxxxix, fig. 481.— ■ P^tel, Couch. Sam., Ill, 1890, p. 152, 



* Margaron ( Unio) eximius Lea, Syn., 1870, p. 28. 



Unio semiquadrata Sowerby, Conch, Icon., XVI, 1866, pi. xlviii, fig. 258, 



* Unio semiquadratus P^tel, Conch. Sam., Ill, 1890, p, 167. 



Siam; Cambodia. 



PHYSUNIO VELARIS Sowerby. 



* Unio vel arts Sowerby, Conch. Icon., XVI, 1868, pi. lxxii, fig. 368. " — *P^tel, 



Conch. Sam., Ill, 1890, p. 171. 



Assam. 



'Fischer believes that the above equals U. micropterus Morelet (Cat., p. 142). I 

 feel sure he is wrong, and that this is a valid species. 



2 1 have only seen the type of this, a very young shell, but it probably belongs to 

 the gravidus group. 



^A compressed shell of a uniform yellow color, probably only a variety of eximius. 



