182 THE ANATOMY OF THE HORSE. 



A reference to Plate 29 will enable the dissector to identify these 

 muscles. 



The Panniculus Carnosus does not form a continuous muscle on 

 the face. It consists of disconnected bundles developed in the sub- 

 cutaneous fascia. It is best developed over the masseter muscle, where 

 it is continuous over the edge of the inferior maxilla with the same 

 structure in the parotideal and intermaxillary regions. On the cheek a 

 few bundles reach the angle of the mouth, in whose retraction they 

 assist. 



Below the rim of the orbit there is found a thin layer of pale muscular 

 fibres and intermediate fascia, which may be viewed as part of the 

 facial panniculus. It wrinkles the overlying skin. This is the lachry- 

 mal muscle of French authors, and the inferior palpebral muscle of 

 Leyh. 



The Levator Labii Sdpbrioris Al^qub Nasi (Plate 29). This 

 muscle has a narrow, thin, and aponeurotic m~igin from the frontal 

 and nasal bones, below and internal to the orbit. It passes over 

 the levator labii saperioris proprius ; and, widening as it descends, 

 it divides into an auterior and a posterior branch, between which 

 the lateral dilator of the nostril emerges. The anterior is the 

 larger branch, and it passes beneath the last-mentioned muscle to 

 end in the outer wing of the nostril and the adjacent part of the 

 upper lip. The posterior branch is inserted into the angle of the 

 mouth. 



Action. — To dilate the nostril and elevate the upper lip by its 

 anterior branch ; to raise the angle of the mouth by its posterior 

 branch. 



The Levator Labii Superioris Proprius (Plates 29 and 30, and Fig. 

 21). By its superior extremity, which is rounded and fleshy, this 

 muscle takes origin below the orbit, from the malar and superior maxil- 

 lary bones. Becoming narrower and thicker, it passes downwards and 

 forwards beneath the last-described muscle, whose direction it crosses. 

 Appearing in front of this muscle, it lies on the false nostril ; and here its 

 muscular portion is succeeded by a narrow tendon, which passes inwards 

 above the superior commissure of the nostril to gain the upper lip. In 

 the lip it passes over the transverse dilator of the nose ; and, approach- 

 ing the muscle of the opposite side, it becomes united to it across the 

 middle line by an intermediate fascia, and is inserted into the texture of 

 the upper lip. 



Action. — Acting together the right and left muscles elevate the upper 

 lip vertically. When the muscle of either side acts singly the lip is 

 raised and inclined towards that side. 



The Dilatator Naris Lateralis. (Doubtfully the homologue of 

 the caninus of man) (Plate 29). This muscle is triangular in form. 



