76 THE EVOLUTIONIST AT LARGE. 



him as a tertium quid, a middle term, from 

 which the horse has varied in one direction 

 and the tapir in another, each of them exag- 

 gerating certain special peculiarities of the 

 common ancestor and losing others, in accord- 

 ance with the circumstances in which they 

 have been placed. Science is now perpetu- 

 ally discovering intermediate forms, many of 

 which compose an unbroken series between 

 the unspecialised ancestral type and the 

 familiar modern creatures. Thus, in this 

 very case of the horse, Professor Marsh has 

 unearthed a long line of fossil animals which 

 lead in direct descent from the extremely un- 

 horse-like eocene type to the developed Arab 

 of our own times. Similarly with birds, 

 Professor Huxley has shown that there is 

 hardly any gap between the very bird-like 

 lizards of the lias and the very lizard-like birds 

 of the oolite. Such links, discovered afresh 

 every day, are perpetual denials . to the old 

 parrot-like cry of ' No geological evidence for 

 evolution.' 



