XIL] "THE ORIGIN OF SPECIES." 317 



the difficulty by supposing extinction ; but where was 

 the slightest evidence that such intermediate forms 

 between birds and reptiles as the hypothesis required 

 ever existed ? And then probably followed a tirade 

 upon this terrible forsaking of the paths of "Baconian 

 induction." 



But the progress of knowledge has justified Mr. 

 Darwin to an extent which could hardly have been 

 anticipated. In 1862, the specimen of Archceopteryx, 

 which, until the last two or three years, has remained 

 unique, was discovered ; and it is an animal which, in 

 its feathers and the greater part of its organisation, 

 is a veritable bird, while, in other parts, it is as dis- 

 tinctly reptilian. 



In 1868, 1 had the honour of bringing under your 

 notice, in this theatre, the results of investigations 

 made, up to that time, into the anatomical characters 

 of certain ancient reptiles, which showed the nature 

 of the modifications in virtue of which the type of 

 the quadrupedal reptile passed into that of a bipedal 

 bird ; and abundant confirmatory evidence of the 

 justice of the conclusions which I then laid before 

 you has since come to light. 



In 1875, the discovery of the toothed birds of the 

 cretaceous formation in North America by Professor 

 Marsh completed the series of transitional forms 

 between birds and reptiles, and removed Mr. Darwin's 

 proposition that "many animal forms of life have 

 been utterly lost, through which the early progenitors 

 of birds were formerly connected with the early 

 progenitors of the other vertebrate classes," from 



