PREFACE. 



Having been intrusted by the Administrators of 

 the Museum, with the publication of this work, 

 it was my duty to comply with their request ; 

 but I should have found myself unequal to the 

 task, had not the Professors themselves furnished 

 me with the means. From them I received 

 much assistance, both by verbal and written in- 

 structions ; more especially in those parts of the 

 science with which I was less acquainted, in 

 consequence of their having less reference to 

 that branch which is the particular object of my 

 attention. 



I have been also considerably assisted in the 

 descriptive part of this work, by several of the 

 gentlemen employed as assistant naturalists in 

 the Museum, and whose care it is to prepare and 

 arrange the collections for the galleries. M. Va- 

 lenciennes furnished me with a list and descrip- 

 tion of all the vertebrated animals, as well as of 

 the mollusca and zoophytes ; to which M. Dufresne 

 has added an account of the shells. M, Latreille 

 took upon himself to trace out the article for the 



