866 " PROCEEDINGS OF THE NATIONAL MUSEUM. 



tCASTALINA PSAMMOICA d'Orbigny. 



* Unio _2>s«mMioica d'Orbkjny, Guer. Mag., 1835, p. 35 ; * Voy. Am. Mer., 1843, p. 608, 



pi. Lxxi, figs. 4-7.— ' KusTER, Conch. Cab. Unio, 1861, p. 263, pi. lxxxviii, 



fig. 4. 

 "^ Castalina psammoica YON Ihering, Arch. fiirNat., 1893, p. 79. 

 ""Marrjaron {Unio) psammoicus Lea, Syn., 1852, p. 19; 1870, p. 30. 



* Unio psammoicus H. and A. Adams, Gen. Rec. Moll., II. 1857, p. 498.—* Sowerby, 



Conch. Icon., XVI, 1868, pi. xciii, fig. 507.— * P/etel, Conch. Sam., Ill, 

 1890, p. 164. 



Tributaries of the Rio de la Plata. 



tCASTALINA UNDOSA von Martens. 



""Castalia undosa Von Martens, S. B.Nat. Fr., 1885, p. 148; * Conch. Mitth., Ill, 

 1885, p. 19, pi. XLii, figs. 2, 3.— PiETEL, Conch. Sam., Ill, 1890, p. 190.— voN 

 Ihering, Arch. fiirNat., 1893, p. 84.— * Nehring, Jl.de Conch., 1894, p. 82. 



Southern Brazil. 



(Group of Gastalina orhignyi.) 



Shell irregularly rhomboid, somewhat compressed, equilateral, ante- 

 rior end rounded, posterior truncate, having a wide, shallow, radiating 

 furrow above the rounded posterior ridge which causes a sinuosity in 

 the outline; epidermis brownish yellow, hinge crenate; one pseudo- 

 cardinal in the left valve and two in the right, which are jagged or 

 somewhat broken up; laterals elongate and striate. 



CASTALINA ORBIGNYI Hupe and Deville.i 



* Pwio orhignyi Hupe and Deville, Rev. et Mag., 1850, p. 645, pi. xvi, fig. 1.— 



*H. and A. Adams, Gen. Rec. Moll., II, 1857, p. 495. 

 ""Margaron ( Unio) orhignyi Lea, Syn., 1852, p. 24; 1870, p. 37. 

 *Unio orhignyana Hupe, Moll. Nouv., Ill, 1857, p. 83, pi. xvii, fig. 1. 



* Unio d'orhignyanus Sowerby, Conch. Icon., XVI, 1868, pi. xcvi, fig. 523. 



* Unio orhignyanns P/etel, Conch. Sam., Ill, 1890, p. 162. 



Upi3er Amazon. 



Genus CASTALIELLA Simpson, 1900. 

 (Type, Castalia sulcata Krauss.) 



Shell subtriangular, greatly inflated, subsolid and strongly sulcate; 

 beaks high, tlie sculpture regularly radiate; posterior ridge well defined 

 and sharp; epidermis reddish chestnut; hinge line narrow, arched; there 

 are two vertically striate pseudocardinals in the right valve, separated 

 by a parallel sided socket, the lower the larger and split, and three in the 

 left standing side by side, the middle one the largest, the lower two 

 torn, with a few small tubercles in each valve behind them ; one granular 



'I do not know just where to place this species, never having seen it, and the 

 descriptions not being full in essential details. It is prohably a Castalina. No men- 

 tion is made of sculpture, but from the figure it seems to be slightly sulcate. 



