894 PROCEEDINGS OF THE NATIONAL MUSEUM. 



fDIPLODON MUTABILIS Lea. 



*Unio mHtaUUs Lea, Pr. Ac. N. Sci. Phila., Ill, 1859, p. 152; *J]. Ac. N. Sci. Phila., 

 IV, 1860, p. 248, pi. xxxvn, fig. 127 ; * Obs., VII, 1860, p. 66, pi. xxxviii, fig. 

 127.— * PiETEL, Couch. Sam., Ill, 1890, p. 160. 



*Marriaron (Unio) mutabilis Lea, Syn., 1870, p. 53. 



Murray River, Australia. 



Subgenus L^VIROSTKIS Simpson, 1900. 



(Type, Unio stagiiorum Dautzenberg.) 



Shell irregularly quadrate, thin, inequilateral, compressed, rounded 

 and narrowed in front, somewhat biaiigulate and truncate behind; 

 beaks rather low, without sculpture;^ surface finely concentrically 

 grooved; epidermis delicately lamellated and serrate; pseudoctirdinals 

 small; laterals elongated; anterior muscle impressions small, well 

 marked; posterior scars suj^erflcial; nacre bluish- white. 



Animal unknown. 



DIPLODON STAGNORUM Dautzenberg. 



* Unio stagnorum Dautzenberg, Bull. Acad. Belg., XX, 1890, p. 372, pi. i, figs. 7, 10. 



Kongo Eiver, Africa. 



The following are unfigured and uncertain species. 



* Unio depressa d'Orbign Y, Guer. Mag., 1835, p. 34. ^ 



* Unio fokkesi Dunker, Zeits. fiir Mai., IX, 1853, p. 54. 



Rio de la Plata, Brazil, According to von Ihering, this= U. loheat- 

 leyanus Lea. 



* Unio Icoseretzi Clessin, Mai. Bl., X, p. 172. 

 River Guahyba, Brazil. 



* Unio macropterus Dunker, Zeits. fiir Mai., Ill, 1846, p. 109. 



Brazil. 



* Unio paraguaniis von Martens, S. B, Ges. Nat. Fr., 1895, p. 



* Unio zealandicus PiETEL, C. Sam., Ill, 1890, p. 172. Said to be of Gray. Where? 

 Unio damnoica T)'ORiiiG]<!Y. Where? 



Unio guahybw voN Ihering. 

 Unio (vtlriopiformis VON Ihering. 

 Unio hishoffi VON Ihering. 

 Unio sebasfana'. von Ihering. 

 Unio iheringi voN Clessin. 



1 According to Dautzenberg the beaks of the remarkable species on which I have 

 founded the above subgenus are completely smooth. It has the appearance of a 

 Diplodon in all other respects, according to the figures and description. Dautzen- 

 berg does not very carefully describe the teeth. 



2 According to d'Orbigny (Voy. Am. Mer., j). 611 ), this species, which he says is the 

 depressa of Lamarck, is found in Chile, near Valparaiso. It can not be Lamarck's 

 species. 



