51 



into many parts, much has been done, but 

 when we consider the vast field yet remain- 

 ing to be explored, we must admit that 

 there will still be left enough to employ our 

 naturalists for many years. Our Crustacea 

 have been thoroughly investigated by Mr, 

 Say in the Journal of the J^cademy of JVa- 

 tural Sciences. We are not aware that any 

 other American has devoted the least atten- 

 tion to this very singular group of animals. 

 The extensive labors of Mr. Say leave us 

 the less to regret on this account Some 

 idea may be conceived of the vast extent 

 of the department of Entomology when we 

 are assured that our naturalists are already 

 acquainted with about nine thousand North 

 American species. Mr. Say and Captain 

 Le Conte, in the Transactions of the socie- 

 ties of New- York and Philadelphia, have 

 furnished materials towards a system of 

 American Entomology. The want of a 

 good entomological manual is still felt by 

 our young naturalists ; this is indeed par- 

 tially supplied by the American Entomology 

 of Mr. Say, of which the second volume has 

 recently appeared, but its expensive form 



