THE HEAD AND NECK 



101 



lateral muscles of the neck. The head of man, nicely 

 balanced on the top of the vertebral column, does not 

 require any such great development of these parts, and 



Fig. 16. — Side view of the skull of horse, with the bone 

 removed so as to show the whole of the teeth, n, nasal 

 bone ; r>, orbit ; z 9 zygomatic arch ; t, temporal fossa ; 

 o(' y occipital condyle; em, external auditory opening; g, 

 glenoid fossa for articulation of the lower jaw ; i\, i 2 , i 3 , 

 the three incisor teeth ; <?, the canine ; pm l , the situation 

 of the rudimentary first premolar, which has been lost 

 in the lower, but is present in the upper jaw ; pm 2 9 pm a 9 

 and pm\ the three fully-developed premolar teeth ; m\ 

 m 2 9 and m 3 9 the three true molar teeth. 



they are, consequently, in a quite rudimentary condition 

 in him. 



On the lateral surface of the skull, the opening (em) 

 which leads to the internal ear, or true orphan of hearing 1 



