TEE VEETEBEAL CONSTITUTION OF THE SKELETON. 



121 



In the four classes of vertebrata, the head is constantly formed of four 

 vertebras, which are determined as follows :" l 



The number of cephalic vertebrse is invariable, as each is destined to 

 lodge the organs of one of the four senses. The occipito-hyoideal lodges the 

 principal organs of hearing; the parieto-maxillary osteodesm protects the 

 sense of taste ; finally, the organs of vision are sustained by the fronto-man- 

 dibular vertebra, while the naso-turbinal contains the sense of smell. 



It was therefore with reason that Geoffrey Saiut-Hilaire and Professor 

 Owen proclaimed that the type of construction of the vertebrated animals is 

 the vertebra 



SECOND SECTION. 



THE ARTICULATIONS. 



CHAPTER I. 



THE ARTICULATIONS IN GENERAL. 



THE different pieces constituting the solid framework of the animal body 

 are, as has been said, united in such a manner that they can move one upon 

 the other From this union results the articulations or articular joints, whose 

 construction will now be referred to in a general manner, before commencing 

 a particular description of each 



To form articulations, the bones correspond to each other by certain 

 points of their periphery, which are named articular surfaces. Every articu- 



1 Lavocat, l Nouvelles e'tudes sur le systeme vertebral,' 1860. 



