4 THE MAMMALIA. 



was Goethe again who is indebted to d' Alton for 

 some of his most frequently quoted opinions. 

 Goethe, in order, as it were, to keep off the prof unum 

 vulgus, gives in a mystic form what d' Alton stated 

 unequivocally. D'Alton's famous work on skeletons 

 also induced Goethe to discuss the subject of adapt- 

 ability, and to maintain that adaptation was one 

 of the most important factors in producing new 

 forms. * The animal is formed by circumstances 

 for circumstances.' 



The power of an organism to accommodate 

 itself to the place of its abode and food which is 

 an undisputed phenomenon must be all the more 

 striking the more complicated the structure of the 

 group of animals, and can therefore generally be 

 more easily verified in the case of the mammal, 

 even by the unpractised eye. As the mammal, in 

 the first place, endeavours to satisfy its need of 

 food, the variation called forth by the adaptation 

 directed towards this want is expressed at first by 

 its instruments of locomotion and mastication. It 

 may also be said that mammals give more proof of 

 the power of adaptation in the systematic arrange- 

 ment of their parts than most of the other classes 

 of animals, but we must not forget that this 

 arrangement of parts, in all classes of animals, is 



