X INTRODUCTORY AND EXPLANATORY 



with the old lady who said that the discovery of all these 

 strange animals did not surprise her so much as the fact 

 that anyone should know their names when they were found. 

 The real trouble is that there are no common names for 

 these animals. Then, too, people who call for easier names 

 do not stop to reflect that, in many cases, the scientific 

 names are no harder than others, simply less familiar, and, 

 when domesticated, they cease to be hard: witness mam- 

 moth, elephant, rhinoceros, giraffe, boa constrictor, all of 

 which are scientific names. And if, for example, we were 

 to call the Hyracotherium a Hyrax beast it would not be a 

 name, but a description, and not a bit more intelligible. 



Again, it is impossible to indicate the period at which 

 these creatures lived without using the scientific term for it 

 Jurassic, Eocene, Pliocene, as the case may be because 

 there is no other way of doing it. 



Some readers will doubtless feel disappointed because 

 they are not told how many years ago these animals lived. 

 The question is often asked How long ago did this or 

 that animal live? But when the least estimate puts the 

 age of the earth at only 10,000,000 years, while the longest 

 makes it 6,000,000,000, it does seem as if it were hardly 

 worth while to name any figures. Even when we get well 

 toward the present period we find the time that has elapsed 

 since the beginning of the Jurassic, when the Dinosaurs 

 held carnival, variously put at from 50,000,000 to 6,000,000 

 years; while from the beginning of the Eocene, when the 

 mammals began to gain the supremacy, until now, the 

 figures vary from 3,000,000 to 25,000,000 years. So the 

 question of age will be left for the reader to settle to his or 

 her satisfaction. 



The restorations of extinct animals may be considered 

 as giving as accurate representations of these creatures as 

 it is possible to make; they were mainly drawn by Mr. 

 Knight, whose name is guarantee that they are of the 



