THE PHYSIOLOGY OF THE MOUTH. 199 



to raise the velum palati ; whence the horse expires and 

 inspires through the nostrils, save in coughing. That act 

 being a spasmodic effort, the muscles, independent of the 

 will, simultaneously contract when those situated within 

 the soft palate are exerted, lift the velum palati, and the 

 breath is sent through the mouth. 



The soft palate is formed by much glandular substance 

 with a small quantity of muscular fibre, which is rather 

 pale in colour. The muscles moving the soft palate are 

 two. The LEVATOR PALATI {single), situated in the middle 

 of its substance ; and the depressors of the soft palate {a 

 pair), each consisting of a disgregated bundle of fibres de- 

 veloped upon the lateral and internal portion of the mem- 

 brane. The action of the last named pair of muscles is to 

 depress the soft palate, or hold it in its place, resting upon 

 the epiglottis. The levator palati is the much more power- 

 ful muscle ; hence we can understand why, when a horse 

 is much pushed, or approaching to the final termination 

 of life, and nature, striving to prolong existence, causes all 

 the muscles to be spasmodically contracted, the velum 

 palati is frequently raised, and the animal breathes through 

 his mouth. 



The sides of the mouth (for as to cheeks the horse can- 

 not be said to possess any) are composed of two muscles, 

 with gland, integuments, &c. The caninus, which is the 

 exterior of the two. Origin. From a glistening tendon, 

 arising from the inferior maxillar, near to the coronoid 

 process. Insertion. Into the inferior border of the superior 

 maxillar as forward as between the molar teeth and the tushes, 

 and into the same part of the upper margin of the lower jaw. 



Buccinator. Origin. By tendon, from the superior 

 border of the lower jaw, near the joint ; and from the tube- 

 rosity of the superior maxillar, near to the velum palati. 

 Insertion. Into the inferior border of the upper, and the 

 superior border of the lower jaw, and by tendon into the 

 angle of the mouth. 



The fauces {Plate VI. g) are a part at which several 

 structures meet. They have no distinct anatomical exist- 

 ence ; yet it is found convenient to apply this name to a 

 kind of neutral ground, formed by many different parts 

 joining one another, but properly belonging to none in par- 



