70 CYCLOPEDIA OF LIVE STOCK AND COMPLETE STOCK DOCTOR. 



Economy of the Head. — We have heretofore spoken of the l)ones of 

 the iicad hciiiiz; in ])airs. So also are the various organs of the hody as 

 a rule, namely : the ears, eyes, nostrils, lips, the lobes of the lungs, the 

 va'ives of the heart,, the kidneys, etc. Thus the two frontal bones (a) 

 make up the forward part of the head. The wall bones (b) cover the 

 outer lobes of the large portion of the brain. The occipital bone (d) is 

 strong and solid, and at its back contains the spinal marrow, and some 

 nerves and arteries which pass from the brain ; at the point where it is 

 jointed to the lirst.bone of the nock it is rounded and smoothed to make 

 the articulation perfect. The sphenoid bone (^) forms the hiferior and 

 central part of the skull (cranium). Near the bones of the face (facial 

 6o?ies), are sinuses or channels, that are named from the bones which 

 they pierce or channel. The bones of the head are of two kinds, the 

 soft and scaly, (squamous), and the hard, (petrous), hones. The temporal 

 bones are likewise of both kinds ; the hard portion contains the organ 

 of hearing, and on its inside surface are openings for the passage of the 

 auditory nerve, and on its outside larger openings for the passage of sound. 

 n. Muscles of the Head and Neek. 



The muscles of the head are not many. Those of the mouth, nostrils, 

 ears and neck, are the most important from the standpoint of the breeder. 

 Cut 3 on the next page we give shows, at two views, the various muscles of 

 the head and neck. 



The Muscles of the Head. — n, the cheek, {Massctcr) muscle ; b, tem- 

 poral muscle, ( tetnporalis) ; c, circular nuiscle, (oi-bicular is), surrounding 

 the eye ; d, the raising muscle, (levator) ; e, orbicularis ovis ; f, the di- 

 lator naris lateralis ; y, Zygomaticus; h, nasalislabii superioris; i, de- 

 pressor labii inferioris. 



Muscles of the Neck. — j, complexus major ; k, splenius; I, levator an- 

 gull scapulae ; m, Hyoideus; n, sterno-maxillaris ; o, levator humeri oi 

 deltoides. The massetcr (a), forms the cheek of the horse, extending 

 along a ridge by the side of the head, below the eye to the rounded angle 

 at the rear of the lower jaw ; its function is to close the jaw. The tem- 

 poral muscle, (b), also assists in the action, and the dimpling seen above 

 the eye in the process of chewing, arises from the action of tliis nuiscl© 

 while opening and closing the jaw. 



The action of the muscle orbicularis is to close the eye-lids. Above 

 the eye, passing inward and upward, over this muscle is the levator nmscle 

 (d). Its office is to raise the upper lid. 



The nxuscles of the ear are not conspicuous. Oi>e of them proceeds 

 from the base of the ear, extends forward and turns the ear forward. 

 The second, situated l)eliind the car, turns it inward and backward, while 

 the third muscle, a narrow st«-ip, descends at the back of the chee»i, and 

 turns the ear outward. 



