Vlll PREFACE. 



" The general division of reptiles, by my friend 

 M. Brouguiart, I have thought it right to pro- 

 cure, but I have made very laborious anatomical 

 researches to establish the ulterior subdivisions. 

 On the fishes, it will probably be found that I 

 have done more than in the rest of the ver- 

 tebrated department. In consequence of the 

 great accessions made to our museum in this 

 way, I have been enabled to add many sub- 

 divisions to those of M. de Lacepede : I have 

 also been enabled to authenticate many species 

 noticed by Commerson and other travellers. 

 My division of this class, is perhaps not so 

 convenient for me, but I believe it is more 

 natural than any preceding one, and should 

 another be established more convenient, and 

 equally conformable to organization, I shall be 

 happy to adopt it. 



" In the general division of the invertebrated 

 animals, I have pursued the plan formerly in- 

 dicated in my memoir, in 1795. The classifi- 

 cation of the rnollusca in particular, on which 

 it is well known, how much labour I have ex- 

 pended, especially on the naked rnollusca, de- 

 pends entirely on my own observations. I 

 have verified every fact furnished by that skil- 

 ful anatomist, M. Pole, concerning the multi- 

 valves and bivalves, and have marked, as I 



