ITS PLACE IN NATUKE. 7 



away the idea that the record is yet perfect. Before 

 the commencement of the Eocene period it is wrapped 

 in what appears at present impenetrable darkness 

 and mystery. 



Throughout the vast Tertiary period, fragments 

 here and fragments there stand out among the ruins, 

 from which we endeavor to reconstruct our edifice, 

 just as the skillful architect or antiquary, from the 

 shattered pieces of marble or stone of an ancient 

 temple, will restore to us the noble forms and pro- 

 portions it once bore. 



The outcome of all recent work in this subject 

 has been, that every fresh discovery which has been 

 made has tended to corroborate, and nothing has 

 been found inconsistent with, the view that the liv- 

 ing beings which we see around us have been gradu- 

 ally fashioned into shape by the modification of 

 pre-existing forms — a view of creation which is the 

 grandest, most sublime, and at the same time most 

 reasonable, which has yet been presented to us. 



A few words may be said here upon the impor- 

 tant subject of specialization, which will be so fre- 

 quently referred to in what follows. The modifica- 

 tions in animal structure which come under this defi- 

 nition may be grouped under three principal head- 

 ings : (1) The addition of parts not met with in the 

 generality of animals, and, as far as is known, not 



