108 THE STRUCTURE OF THE HORSE. 



muscles required to support and move so heavy a 

 head, projecting forwards at the end of so long a 

 neck. Above, on each side, are the " occipital crests," 

 joining in the middle line to form the " occipital pro- 

 tuberance," to which that remarkable structure, the 

 "nuchal," or " cervical ligament," to be spoken of 

 further on, is attached. On each side a large, wing- 

 like process (par-occipital) # descends, for the attach- 

 ment of the great lateral muscles of the neck. The 

 head of man, nicely balanced on the top of the verte- 

 bral column, does not require any such great devel- 

 opment of these parts, and 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 organ 

 of hearing (embedded in the bones which form the 

 side wall of the brain-case), will be seen, to the 

 roughened margin of which the base of the cartilag- 

 inous " pinna," or projecting external ear, is attached. 

 Although we commonly speak of this latter as the 

 " ear," as it is the only externally visible part of the 

 complicated organ by which sounds are recognized, 

 it is a mere accessory, the use of which is to aid in 

 collecting the vibrations passing through the air, 



* This is the " styloid process " of veterinary anatomy, 

 but not to be confounded with the parts bearing the same 

 name in human anatomy. 



