406 THE MOUNTAIN. 



THIRD GREAT DIVISION OF THE ANIMAL 

 KINGDOM; OR, ANIMALIA ARTICULATA. 



OP this division Cuvier observes : " This third general 

 form is as well characterized as that of the Vertebrata ; the 

 skeleton is not internal as in the latter, neither is it annihi- 

 lated as in the Mollusca, the articulated rings which encircle 

 the body, and frequently the limbs, supply the place of it, 

 and as they are usually hard, they furnish to the powers of 

 motion all requisite points of support, so that here, as among 

 the vertebrata, we find the walk, the run, the leap, natation, 

 and flight." 



The Articulata are distributed into four classes. These 

 are the Annulata, Crustacea, Arachnides, and Insecta. 



CLASS I. ANNULATA. 



Only Invertebrates with red blood. Nearly all inhabit 

 water, the earth-worms excepted. This class is divided into 

 three orders, based on organs of respiration. 



ORDER I. TUBICOLA. 



Mostly inhabit tubes. Breathing arrangement, tufts or 

 arbusculae attached to head. These sea-worms are numer- 

 ous, living in mud or sand, and making tubes of lime and 

 other substances. 



ORDER II. DORSIBRANCHTATA. 



Branchiae or breathing organs distributed along the body, 

 arborescent, or tuft-like in shape, "ramified in laminae or 



