866 PROCEEDINGS OF THE NATIONAL MUSEUM. 



tCASTALINA PSAMMOICA d'Orbigny. 



*Unio j)8iwiotcai>'Ouni<;NY,Guer. Mag., 1835, p. 35; * Voy. Am. Mer.,1843, p. 608, 

 pi. LXXI, figs. 4-7. ' KrsTKR, Conch. Cab. Unio, 18(51, p. 263, pi. LXXXVIII, 

 fig. 4. 



^Castalina psammoica vox IHKRING, Arch, fiir Nat., 1893, p. 71). 



'Muryaroti (Unio) psannnoicus LEA, Syn., 1852, p. 19; 1870, p. 30. 



* Unio psammoicns H. and A. ADAMS, (Jen. Roc. Moll., II. 1857, p. 498. * SOWEKBY, 



Conch. Icon., XVI, 1868, pi. xcm, fig. 507. * P^ETEL, Conch. Sam., Ill, 

 1890, p. 164. 



Tributaries of the Kio de la Plata. 



tCASTALINA UNDOSA von Martens. 



*CastaUa nndosa VON MARTENS, S. B.Nat. Fr., 1885, p. 148; * Conch. Mitth., Ill, 

 1885, p. 19, pi. XLII, figs. 2, 3. PyETEL, Conch. Sam., Ill, 18i)0, p. 190. VON 

 IHKRIXG, Arch, fiir Nat., 1893, p. 84. * NEHRIXO, Jl.de Conch., 1894, p. 82. 



Southern Brazil. 



(Group of Castalina orbignyi.) 



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. 1 



*Unio orbignyi 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) orbignyi LEA, Syn., 1852, p. 24; 1870, p. 37. 



* Unio orbignyana HUPE, Moll. Nouv., Ill, 1857, p. 83, pi. xvn, fig. 1. 



* Unio d'orbiynyanus SOWERBY, Conch. Icon., XVI, 1868, pi. xcvi, fig. 523. 



* Unio orbignyanus P/ETEL, Conch. Sani., Ill, 1890, p. 162. 



Upper Amazon. 



Genus CASTALIELLA Simpson, 19OO. 

 (Type, Castalia sulcata Krauss.) 



Shell subtriangular, greatly inflated, subsolid and strongly silicate; 

 beaks high, the sculpture regularly radiate; posterior ridge well denned 

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

 are two vertically striate pseudocardiuals 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 



1 1 do not know just where to place this species, never having seen it, and the 

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

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



