STRUCTURE OF THE VERTEBRAL COLUMN. 



471 



should be the same in all the Mammalia ; even the long- 

 necked Giraffe having only seven, while the Whale, whose 

 head seems to be joined to its body without the intervention 

 of any neck, also has seven cervical vertebrae, although they 

 are almost as thin as a sheet of paper. It is owing to the 

 small number of joints in its neck, that the movements of the 

 head of the Giraffe are far less graceful than those of the 

 Swan and other long-necked Birds, in which the number of 

 cervical vertebrae is much greater. The following table shows 

 the number of vertebrae in animals of different groups. 



We see from the above table, that it is by the multiplica- 

 tion of the coccygeal vertebrae, that the tail is prolonged in 

 those animals which possess it. In fact, it is only in Man, 

 and in those of the Ape tribe which approach nearest to him, 

 that the number of these vertebrae is as low as 4. 



