EVIDENCE FROM PALAEONTOLOGY 99 



again this oft-told tale, which has been reiterated 

 until it has become a hackneyed commonplace. 

 Friends and foes of evolution are alike given to 

 sneering at it and calling it the " parade horse," the 

 '' hobby horse," the '' stalking horse," and other 

 opprobrious names, seeming almost to imagine that, 

 if testimony be very often repeated, it loses all 

 validity. Logically, this is on a par with the pro- 

 cedure of the ship's crew in the "Hunting of the 

 Snark," who believed that, by repeating a state- 

 ment three times, they proved it. On the other 

 hand, no sketch, however slight, which purports to 

 give an outline of the evidences of evolution, can in 

 fairness omit all mention of this remarkable case. 



The Recent and Pleistocene horses, including in 

 that term not only the true horses, but also the 

 asses, zebras, etc., have a skeleton which is wonder- 

 fully adapted to swift running, while their teeth are 

 highly specialized and elaborated for the masticating 

 of grasses, which are among the most abrasive of 

 plants. The front teeth (incisors) used for cropping, 

 continue to grow for a long period and have on their 

 biting surfaces a deep pit, lined with enamel, which 

 horsemen call the : 'mark.' : The grinding teeth are 

 very high-crowned, growing persistently in height, 

 as they are worn down, to an advanced period of 

 life, when the formation of roots puts an end to 

 growth; they have masticating surfaces which are 

 kept rough by the different hardness of the three 

 substances exposed on these surfaces, dentine, 



