INTRODUCTION. CV 



that it is scarcely possible, in order to prove 

 the adaptation of means to an end, to treat 

 satisfactorily of the former without occasional 

 illustrations from the latter. After the doctor's 

 work appeared, I removed many things of 

 this kind from my MS., upon which he had 

 enlarged. The moult of Crustaceans, how- 

 ever, seemed to me, and to every friend whom 

 I consulted, so necessary to make the history 

 of that Class complete, that, though mostly 

 derived from the same source as that of my 

 learned Co-nominee, I did not expunge it. 



