Professor L. Agassi/, Professor L. R. G-ibbes, Pro- 

 fessor Joseph Leidy and John McCradt, Esq., have 

 kindly tendered their services in describing some of 

 the new species of Fossil Fish, Crustacea, Mammalia 

 and Echinodermata, for publication in this work ; the 

 initials of those authors will be found under their re- 

 spective articles. 



