76 PROCEEDINGS OF THE ACADEMY OF 



broso-fuscata, eradiate et marginata; dentibus cardinalibus sublongis, sub- 

 obliquis, crenulatis, lamellatis, ia utroque valvulo duplicibus ; lateralibus 

 praslongis, obliquis, lamellatis corrugatisque ; margarita alba, et valde irides- 

 cente. 

 Hab. China ; A. R. Wright, M. D. 



Unio tortuosus.^ Testa, imequivalva., contorta, plicata, valde obliqua, in- 

 flata, postice obtuse angulata, antice oblique curvata ; valvulis percrassis. an- 

 tice crassioribus ; uatibus promiaentibus, crassis terrainalibusque ; epidermide 

 tenebroso-oliva., obsolete radiata ; dentibus cardinalibus permagnis, crassis, 

 rectis corrugatisque ; lateralibus sublongis, subrectis, striis perpendicularis 

 instructis ; margarita argentea, et valde iridescente. 



Hab. China ; A. R. Wright, M. D. 



This remarkable Unio is the first which has been found possessing an ir- 

 regular plane of the margin and being incequivnlue. When looking on the ante- 

 ' rior end with the ligament above, the line of the opening of the valves curves 

 to the right. The beak of the left valve is higher than that of the right and 

 projects anteriorly. The left valve is therefore larger than that of the right, 

 and the weight differs the left being 257 grains and the right 242 grains. 

 The very remarkable perpendicular striae on the lateral teeth of this speci- 

 men, if always present in other individuals, will demand its being placed 

 in the genus Prisodon, Schumacker = Caslalia, Lam. These stria? are proba- 

 bly normal to the species. Before Triquetra contorta, from China, was des- 

 cribed by me, none of us could have expected to see a member of the Unionidx 

 to be curved likfe Area torluosa, Lin.; but now we have a second member of 

 the family totally unlike the other, except having a curved plane of the shell. 



Unio rufofuscus. Testa, plicata, subquadratii, subsulcata, sublenticulari, 

 insequilaterali, postice rotundata, antice rotunda ; valvulis crassiusculis, an- 

 tice crassioribus ; natibus prominulis, crebre et minute plicatis ; epidermide 

 rufofusca, eradiata, micanti ; dentibus cardinalibus subcompressis, crenulatis, 

 in utroque valvulo subduplicibus ; lateralibus longis subcurvisque ; marga- 

 rita, alba" et iridescente. 



Hab. ? Sig. Patricio Maria Paz. 



May 2d. 



The President, Dr. Bridges, in the Chair. 



Eleven members present. 



The following paper was presented for publication : 

 " Partial Catalogue of the Cold blooded Vertebrata of Michigan, Pt. 

 IL," By E. D. Cope. 



May 9th. 

 The President, Dr. Bridges, in the Chair. 

 Thirteen members present. 



May 16th. 



The President, Dr. Bridges, in the Chair. 



Twenty-four members present. 



The following paper was presented for publication : " Description 

 of eight new Species of Unio of the United States." By Isaac Lea. 



[May, 



