INTRODUCTION. 35 



The Academy of Natural Sciences of riiiladolphia 

 issued the first number of its Journal in 1817. The' 

 Annals of the New York Lyceum of Natural History 

 appeared in 1823. The Contributions of the Maclurian 

 Lyceum in 1827, and the Journal of the Boston Society 

 of Natural History in 1834. Besides these, which arc 

 exclusively appropriated to Natural History, there are 

 others of a mLxed character, in which considerable 

 prominence has latterly been given to the same class of 

 su])jects ; such are the Transactions of the American 

 Philosophical Society, and the Memoirs of the American 

 Academy of Arts and Sciences. Several private Jour- 

 nals also in the same interest, have from time to time 

 appeared ; none of which, however, have obtauied a 

 permanent establishment, except the American Journal 

 of Science and Arts, edited by Professor Silliman, 

 which commenced its career in 1819, and yet enjoys a 

 vigorous existence. This work contains numerous and 

 valuable contributions to zoology, and has always exer- 

 cised a wholesome and effective influence in diffusing 

 correct ideas of the value of all the Natural Sciences. 

 It is in these publications alone, that we must look for 

 the great mass of original materials available in the 

 compilation of any work on the zoology of the United 

 States ; and they are the sources often resorted to in the 

 preparation of these volumes. 



During the last ten years, however, several important 

 works of a different character have appeared. A gen- 

 eral and growing comiction, in the public mind, that the 



