2 The Bird 
the “poems hidden in the bones.” As Professor Huxley 
once said, “Paleontology is simply the biology of the 
past, and a fossil animal differs only in this regard from 
a stuffed one, that the one has been dead longer than 
the other, for ages instead of for days.” 
A great many more fossil mammals and reptiles have 
been discovered than birds, and the reason may perhaps 
be conjectured. The bones and bodies of birds were in 
former times as now very light, and if death occurred on 
the water, the body would float and probably be de- 
voured by some aquatic reptile. Then, again, when some 
cataclysm of nature or change of climate obliterated 
whole herds and even races of terrestrial creatures, the 
birds would escape by flight, and when death eventually 
came, they would be stricken, not in flocks, but singly 
and in widely scattered places as to-day. . 
For perhaps a million years in the past, birds have 
changed scarcely at all,—the bones of this period belong- 
ing to the species or at least genera of living birds. But 
in the period known as the Cretaceous, when the gigantic 
Dinosaurs flourished and those flying reptile-dragons— 
the Pterodactyls—flapped through the air, a few remains 
of birds have been found. Some of these are so com- 
plete that almost perfect skeletons have been set up, 
enabling us vividly to imagine how the bird looked when 
swimming through the waters of our globe, or flying 
through the air, perhaps four millions of years ago. 
The most remarkable peculiarity of these birds was 
the possession of teeth. Two of the most well-known 
examples are called Jchthyornis and Hesperornis. The 
