361 



CHAPTER VI. 



VERTEBRATA. 



1. Vertebrated Animals in general. 



IF it be pleasing to trace the footsteps of nature 

 in constructions so infinitely varied as those of 

 the lower animals, and to follow the gradations 

 of ascent from the zoophyte to the winged in- 

 sect, which exhibits the greatest perfection com- 

 patible with the restricted dimensions of that 

 class of beings, still more interesting must be the 

 study of those more elaborate efforts of creative 

 power which are displayed on a wider field in the 

 higher orders of the animal kingdom. In the 

 various tribes of beings which are now to come 

 before us, we find nature proceeding to display 

 more refined developements in her system of or- 

 ganization, resorting to new models of structure 

 on a scale of greater magnitude than before, de- 

 vising new plans of economy, calculated for more 

 extended periods of duration, and adopting new 

 arrangements of organs, fitted for the exercise of 

 a higher order of faculties. The result of these 

 more elaborate constructions is seen in the vast 

 series of Verlebrated Animals, which comprises 





