A DAN SON. 



excellent work in France on this subject*, which was repub- 

 lished in 1 780, with considerable additions and improvements, 

 by Messrs. Favanne ; there are upwards of 2000 shells figured 

 in this edition, in a manner much superior to that of any 

 which had been published before. In 1757 M. Adanson pub- 

 lished his Histoire Naturelle du Senegal-f, in which he has 

 figured about 1 85 species, and accurately described not only 

 the shells, but also most of the animals contained in them ; 

 these are arranged according to a system of his own invention, 

 taken principally fi*om the structure of the animals. Under 

 most of his species he has placed many varieties that most 

 authors have considered as distinct species ; he has been very 

 particular and minute in his descriptions of the animals, as 

 well as their shells, and has divided them into 30 genera, in 

 four divisions, as follow : 



