Anodonta Uruguayensis. — Testa laevi, obovata, ventricosa, valde inaequilat- 

 erali: valvulis subcrassis, antice paulisper crassioribus ; natibus subelevatis. 

 tumidis ; epidermide tenebroso-oliva, eradiata ; margarita, cseruleo-albil et valde 

 iridescente. 



Ilab. — Uruguay River, S. America. Prof. J. AVyman. 



Descriptions of Four New Species of TJNI0NID.5: from Brazil and Buenos Ayres. 



BY ISAAC LEA. 

 (R«ad March 13th, 1860.) 



L'n'io teifidus. — Testa lam, obliquo-oblonga, ad latere planulata, valde in- 

 sequilaterali, po3tice acute angulata, antice rotunda ; valvulis crassiusculis. 

 antice crassioribus ; natibus prominentibus, ad apices rugose et divaricate un- 

 dulatis; epidermide raicante, luteo-viridi, eradiata; dentibus cardinalibus 

 grandibus, trifidis, sulcatis ; lateralibus longis, crenulatis, in valvule dextro 

 trifidis ; margarita argentea et iridescente. 



Ilab. — Buenos Ayres, Soutb America. M. D'Orbigny. 



Usio patelloides. — Testa, lsevi, subrotunda, subcompressa, suba?quilaterali. 

 antice et postice rotundata ; valvalis subcrassis, antice crassioribus; natibus 

 prominulis, ad apices divaricate undulatis; epidermide tenebroso-castanea. 

 striata, eradiata; dentibus cardinalibus longis, compressis, obliquis, crenulatis 

 eorrugatisque; lateralibus longis, crenulatis cvirvisque ; margarita argentea 

 et iridescente. 



Hah. — Amazon River, Brazil. Captain George Brown. Rio Plata. H.Cum- 

 ing. 



Anodonta Amazosensis. — Testa lajvi, transversa, subinflata, valde inrequi- 

 laterali, postice subbiangulati, antice rotunda; valvulis subcrassis; natibus 

 subelevatis, tumidis ; epidermide micante, tenebroso-viridi, nigricante, vel era- 

 diata vel obsolete radiata ; margarita intus subrosea et valde iridescente. 



Hah. — Upper Amazon, Brazil. CM. Wheatley. 



Anodonta Moricandii. — Testa tevi, oblique quadrata, subinflata, ad latere 

 planulata, valde inaequilaterali, postice obtuse angulata et biante ; antice 

 oblique rotundata et valde biante ; valvulis tenuibus, diaphinis ; natibus sub- 

 prominentibns ; epidermide luteo-oliva. polita, obsolete radiata, margarita 

 cseruleo-alba et valde iridescente. 



Hah. — Bahia, Brazil. S. Moricand, Geneva. 



