90 PROCEEDINGS OF THE ACADEMY OF 



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

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

 Hab. Upper Amazon, Brazil. C. M. Wheatley. 



Anodonta Moricandii. Testa. la;vi, oblique quadrata, subinflata, ad latere 

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

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

 prominentibus ; epidermide luteo-oliva, polita, obsolete radiata, margarita 

 caeruleo-alba. et valde iridescente. 



Hab. Bahia, Brazil. S. Moricand, Geneva. 



Descriptions of Fifteen new Species of Uruguayan TJNIONIDiE. 



BY ISAAC LEA. 



During the winter of 1858-59, R. B.Forbes, Esq., of Boston, whose name has 

 been identified with so many works of philanthropy and public utility, organ- 

 ized an excursion to the La Plata, the Uruguay and Rio Negro rivers, in South 

 America; his object in part being to afford facilities for studying the natural his- 

 tory of the countries bordering on these waters. Professor J. Wyman, who ac- 

 companied him, has most kindly placed at my disposal all the specimens of the 

 Unionidoz which he had been enabled to collect in these extensive southern fresh 

 waters. In this very interesting collection I was surprised to find so many 

 species which had not been before observed. These are now herein described, 

 and consist of eleven Uniones and four Anodonta. The whole number brought 

 of these fresh water Mulluscs, was twenty-three species. Those heretofore de- 

 scribed are Prisodon truncatus, Schum., (Caslalia ambigua, Lam.,) Unio Para- 

 nensis, Lea., U. parallelopipedon, Lea., Anodonta rotunda, Spix, A. trapezalis, Lam., 

 A. laio-marginata, Lea, A. tenebricosa, Lea, A. Blainvilliana, Lea. In addition 

 there were three small species of Cyrena, two of which I have not ascertained, 

 the third is the variegata of D'Orbigny. There was also a small species of 

 Cyclas. 



Unio Wymanii. Testa lsevi, antice subsulcata, quadrata, compressa, ad latere 

 planulata, inaequilaterali, postice obtuse angulata, antice rotundata; valvulis 

 subcrassis, antice crassioribus ; natibus prominulis, ad apices divaricate undu- 

 latis ; epidermide tenebroso-oliva, vel eradiata. vel obsolete radiata ; dentibus 

 cardinalibus compressis, erectis, crenulatis, in utroque valvulo duplicibus ; later- 

 alibus longis, crenulatis subcurvisque ; margarita argentea. et valde iridescente. 



Hab. Uruguay River, S. America. Prof. J. Wyman. 



Unio Ueuguayensis. Testa laevi, antice subsulcata, elliptica, inflata, subequi- 

 laterali, postice obtuse angulata, antice rotundata ; valvulis subcrassis, antice 

 crassioribus; natibus subprominentibus, ad apices divaricate undulatis; epid- 

 ermide virido-fusca, postice tenebricosa, polita, obsolete radiata ; dentibus car- 

 dinalibus compressis, crenulatis suberectisque ; lateralibus longis subrectisque ; 

 margarita argentea et iridescente. 



Hab. Uruguay River, S. America. Prof. J. Wyman. 



Unio piger. TestS, laevi, elliptic^, inflata, subequilaterali, postice obtuse ar.- 

 gulata, antice oblique rotundata ; valvulis crassiusculis, antice paulisper cras- 

 sioribus ; natibus subprominentibus, inflatis, ad apices divaricate undulatis ; 

 epidermide nigro-fusca, striata, obsolete radiata; dentibus cardinalibus com- 

 pressis, crenulatis ; lateralibus sublongis curvisque ; margarita argentea et 

 iridescente. 



Hab. Uruguay River, S. America. Prof. J. Wyman. 



Unio per^eformis. Testa, laevi, subrotunda, inflata, valde insequilaterali, 

 postice obtuse subangulata,, antice oblique rotundata; valvulis subcrassis, an- 

 tice paulisper crassioribus ; natibus vis prominentibus, inflatis ; epidermide 



[March, 



