CHAPTER II 



THE VERTEBRATA OR VERTEBRATES. 

 SECTION I. 



THE VERTEBRATES CONSIDERED AS A BRANCH. 



As already stated on a previous page, the Branch of 

 Vertebrates includes all animals which have an internal 

 jointed skeleton. The form of this skeleton as it appears 

 in Man and Birds is shown in Figs. 24 and 26. 



The skeleton of the Vertebrates forms the framework 

 of the body, and to this framework the flesh is attached, 

 and outside of the whole is the skin, which is naked, or 

 covered with hair, fur, wool, feathers, scales, or plates, ac- 

 cording to the kind of animal. 



The most important portion of the skeleton, or the 

 portion which is the most constantly present, and that 

 to which all the others are directly or indirectly attached, 

 is the axis, called the spinal column or back-bone, at the 



FIG. 23. 



c 

 A Vertebra. 



c, centrum or main body of the vertebra; n, neural canal; t, transverse process; 

 ns, neural spine. 



anterior end of which is the brain-cavity or cranium. This 

 column is made of parts called vertebrae a single part a 

 vertebra, from the Latin verto, to turn. 

 2 



