NATURAL SCIENCES OF PHILADELPHIA. 391 



Descriptions of three new species of Mollusca, of the genus Sphierium, 

 by Temple Prime. 



Dec. 24th. 

 Mr. Lea, President, in the Chair. 



Nineteen members present. 



The following papers were presented for publication : 



Description of a new Qaadrumanous Mammal, of the genus Midas, 

 by J. II. Slack, M. D. 



Description of new Plants from Texas, by S. B. Buckley. 



On the genera Panolopus, Centropyx, Aristelliger and Sphaerodac- 

 tylns, by E. D. Cope. 



Descriptions of eleven new species of the genus Unio from the 

 United States, by Isaac Lea. 



Descriptions of seven new species of the genus Io, by Isaac Lea. 



Monograph of the species of Sphserium of North and South America, 

 by Temple Prime. 



Synopsis of the recent species of Gastrochsenidae, by George W. 

 Try on. 



Synopsis of the Selaginoids, by Theodore Gill. 



Synopsis of the Notothenioids, by Theodore Gill 



Synopsis of the Harpagiferoids, by Theodore Gill. 



Synopsis of the Chaenichthyoids, by Theodore Gill. 



Dr. Slack presented for examination a Guide to the Collection of the 

 Academy, to be printed for sale at the door of the Academy. 



Dec. 31st. 



Mr. Lea, President, in the Chair, 



Thirty members present. 



On report of the respective committees, the following papers were 

 ordered to be printed in the Proceedings: 



Descriptions of Eleven New Species of the genus UNIO from the United States. 



BY ISAAC LEA. 



TJnio sqdamecs. Testa lsevi, suboblonga, valde compressa, inaequilaterali, 

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

 crassioribus ; natibus prominulis ; epidermide vel rufo-fusca vel tenebroso- 

 fusca, striata, inferne squamosa, obsolete radiata ; dentibus cardinalibus sub- 

 grandibus, compressis, striatis, in utroque valvulo subduplicibus; lateralibus prae- 

 longis, lamellatis, obliquis subrectisque ; raargarita alba et valde iridescente. 



Rob. North Carolina. J. G. Anthony. 



Unio rostrum. Testa lasvi, subtriangulari, ad latere planulata, valde inaequi- 

 laterali, postice subbiangulata, antice rotunda ; valvulis crassiusculis, antice 

 paulisper crassioribus ; natibus prominulis; epidermide tenebroso-fusca, nigri- 

 cante, eradiata; dentibus cardinalibus parvis, sulcatis, crenulatis, in utroque 

 valvulo duplicibus; lateralibus longis, lamellatis subcurvisque ; margarita al- 

 bida. et iridescente. 



Hab Davidson County, North Carolina. F. A. Genth, M. D. 



1861.] 



