2 THE MAMMALIA. 



the high estimation in which man holds himself, 

 an opinion which we meet with as uniformly. Man 

 finds himself bound by every fibre within the group 

 of the Mammalia ; and as soon as he makes him- 

 self the standard by which to measure the value 

 and the position of living creatures and this he has 

 every reason to do within the circle of those he is 

 acquainted with he cannot, when making a com- 

 parative survey, do otherwise than class them as 

 they always have been classed. 



The very obvious fact of the close affinity of 

 the Mammalia with man, and the consequent neces- 

 sity for some systematic arrangement of them, leads 

 to the further observation that certain groups or 

 classes of animals resemble the Mammalia in the 

 main characteristics of form and structure more than 

 others. Nor has there ever been any doubt as to 

 this close * relationship.' Ever since the days of 

 Aristotle men have been agreed about the group 

 of the Vertebrates, and about the succession of 

 Fishes, Amphibians, Eeptiles, Birds and Mammals. 

 This order was naturally meant to express the gra- 

 dation of perfection, and always with the supposi- 

 tion of the ideal to be attained in man. Hence the 

 vertebrates, as a whole, formed the chief main divi- 

 sion, the highest type of the animal kingdom. 



