70(1 



then must the bats, anteaters and whales occupy the angles; for we 

 can not otherwise express their dissimilarity inter se and their depar- 

 ture from the type. The subjoined figure expresses this. 



Bats. 



Typical 

 Mammals. 



Whales. 



Anteaters. 



The contents of the group called mammals being thus expressed, not 

 for any hypothetical end, but because their difference from the typi- 

 cal forms and from each other cannot he otherwise expressed, it remains 

 only to arrange the great classes of birds, reptiles and fishes, in 

 places which common sense will at once assign them, as under. 



Birds. 



Bats. 



Mammals. 



Whales. 



Anteaters. 



Fishes. 



Reptiles. 



As I have said before, the Vertebrata have been selected rather than 

 the entire Animal Kingdom, because their divisions are more obvious 

 to those who do not happen to have made structural Zoology their 

 particular study : those who have studied this science, will see that 

 the same formula of arrangement obtains in the primary divisions, and 

 that they range thus : — 



ARTICULATES. 



VERTEBRATES. 



RADIATES. 



MOLLUSCATES. 



