AMERICAN MUSEUM OF NATURAL HISTORY, 



marine Lizards, and other creatures of the A^e of Reptiles. 

 These are millions of years old. Some of the Dinosaurs are the 

 largest known land animals, longer than the width of this hall, and 

 standing on all fours with the back reaching nearly as high as the 

 ceiling. 



The rest of the specimens are mammals (animals which suckle 

 their young, including most four-footed beasts). Most of them 

 are hundreds of thousands of years old, ranging from perhaps 

 three million years down; these lived long before man had 

 appeared on the earth. A few, including the Mastodon, Mam- 

 moth, Megatherium, Irish Elk, One-toed Horse and others, are 

 of the latest geological age (the " Pleistocene "), and, while tens 

 of thousands of years old, were contemporaries of primitive 

 man. 



Many of the extinct animals are allied to animals still living, 

 and are called by the common names of their modern relatives. 

 Thus we have extinct Horses, Rhinoceroses, Tapirs, Camels, etc. 

 Other races have died out completely and are not related to any 

 living animals. For these there is no common name., and we have 

 to coin a name from their (Latin or Greek) scientific name, call- 

 ing them " Titanotheres," " Dinosaurs," etc. 



The best example of Evolution is the race of extinct 

 ancestors of the Horse, shown in the right hand far corner of the 

 hall. Next best is the series of Camel ancestors, on the left hand 

 side near the far end, and the series of ancestors of Titanotheres 

 and ancestors of Rhinoceroses, skulls and skeletons ranged along 

 the right hand (south) side of the hall beginning at the entrance. 

 All these series are arranged according to age, the most ancient 

 (oldest or first stage of evolution, found in the lowest rock-strata) 

 first, the most recent (final stage of evolution, found in the upper- 

 most rock-strata) last. 



