FUNDAMENTAL RELATIONS OF ANIMALS 23 



Comparative Anatomy. ^^ Some naturalists, however, have already 

 extended such comparisons respecting the structure of animals be- 

 yond the limits pointed out by nature, when they have attempted 

 to show that all structures may be reduced to one norm, and when 

 they have maintained, for instance, that every bone existing in any 

 Vertebrate must have its counterpart in every other species of that 

 type. To assume such a uniformity among animals would amount 

 to denying to the Creator even as much freedom in expressing his 

 thoughts as man enjoys. 



If it be true, as pointed out above, that all animals are constructed 

 upon four different plans of structure, in such a manner that all the 

 different kinds of animals are only different expressions of these 

 fundamental formulae, we may ^vell compare the whole animal king- 

 dom to a work illustrating four great ideas, betAveen which there is 

 no other connecting link than the unity exhibited in the eggs in 

 which their most diversified manifestations are first embodied in an 

 embryonic form, to undergo a series of transformations, and appear 

 in the end in that wonderful variety of independent living beings 

 which inhabit our globe, or have inhabited it from the earliest 

 period of the existence of life upon its surface. 



The most surprising feature of the animal kingdom seems, how- 

 ever, to me to rest neither in its diversity, nor in the various degrees 

 of complication of its structure, nor in the close affinity of some of 

 its representatives while others are so different, nor in the manifold 

 relations of all of them to one another and the surrounding world, 

 but in the circumstances that beings endowed with such different 

 and such unequal gifts should nevertheless constitute an harmonious 

 whole, intelligibly connected in all its parts. 



^ Agassiz, "On the Structure and Homologies of Radiated Animals, with Reference 

 to the Systematic Position of the Hydroid Polypi," Proceedings, AAAS, II (1850), 389- 

 396. 



