72 VERTEBRATED ANIMALS. 



her system of organization ; resorting to new models of 

 structure, on a scale of greater magnitude than before ; 

 devising new plans of economy, calculated for more ex- 

 tended periods of duration; and adopting new arrange- 

 ments of organs, fitted for the exercise of a higher order 

 of faculties. 



200. " The result of these more elaborate constructions 

 is seen in the vast series of vertebrated animals, which 

 comprises a well-marked division in zoology, compre- 

 hending all the larger species that exist on the globe, in 

 whatever climate or element they may be found ; and 

 including man himself, placed, as he unquestionably is, 

 at the summit of the scale, the undisputed lord of the 

 creation." 



201. " A remarkable affinity of structure prevails 

 throughout the whole of this extensive assemblage of 

 beings. Whatever may be the size, or external form of 

 these animals, whatever the activity, or sluggishness of 

 their movements, whetner inhabitants of the land or water, 

 or the air, a striking similitude may be traced in the dis- 

 position of their vital organs, and in the construction of 

 their solid frame-work or skeletons, which sustains and 

 protects their fabric. The quadruped, the bird, the 

 tortoise, the serpent, the fish, however they may differ 

 in subordinate details of organization, yet are constructed 

 upon one uniform principle, and appear like varied copies 

 from the same original model. In no instance do they 

 present structures which are altogether isolated, or can 

 be regarded as the results of separate and independent 

 formations." 



202. Animals resist both heat and cold. But although 

 ere is a general analogy with respect to the skeletons of 

 all vertebrated animals, and a general similitude in the 

 disposition and construction of their vital parts, still there 

 is a striking and wonderfyl difference in the effects pro- 

 duced by the action of these parts, especially vital action, 

 on the animal, and particularly on its temperature ; fu r 



What is said concerning the affinity of structure which exists amont> 

 all animals with back bones? What is said of the different effects of vile I 

 action on differant vertebrated animals' 



