FAoiA Ti()\ or Till': noh'sH i.\ .sa/i h'l': :i'> 



the tVt't, clon^atinij; the tooth-crowns to adapt thcinsolvcs to the chan^- 

 m^ conditions around thcni, altliou^li none j)arallcl('d the horse cvohi- 

 tion (juitc so closely as did the |)seudo-hoi-ses of South Anieiica. P»ut 

 the camels in America, the deer, antelope, sheep an<l cattle in the Old 

 World, pro^;resse(l on nuich the same lines of evolution, althouji;h theii- 

 adaptation was not to just the same conditions of life. 



PRINCIPAL STAGES IN THE EVOLUTION OF THE HORSE. 

 SYNOPTIC PANEL 



On the right hand at the entrance to the Horse Alcove is a double 

 panel (pages 36 and 37) showing the chief stages in its evolution. On 

 the right-hand panel is the series of skulls, fore feet and hind feet, each 

 stage set opposite the geological epoch during which it lived. Thus all 

 horses found as fossils in tfie rocks of the Eocene Epoch are Four-toed 

 Horses; all from the Oligocene are small Three-toed Horses with short- 

 crowned teeth, and so on. 



On the left-hand panel is a corresponding series of palates to show 

 the gradual change in pattern of the upper teeth, and convenion of the 

 premolars into 'niolaiifoim' grinders; and a series of single teeth to 

 show the progressive lengthening of the crown. The change in the l)rain, 

 the foie leg and hind leg aie also shown in this panel, and ^ide views of 

 the foic and hind foot show more cleaily the sta":es in reduction of the 

 .^■i^Ie tees. 



