204 



ANIMAL MECHANICS. 



Outer Layer. 



1. Quadratics labii superioris (levator labii superioris). 



2. Orbicularis malaris. 



3. Zygomatici (major et minor). 



4. Risorius. 



5. Subcutaneus colli (platysma). 



6. Triangularis oris (depressor anguli oris). 



Inner Layer. 



7. Quadratus labii inferioris (quadratus menti). 



8. Buccinator. 



9. Caninus (levator anguli oris). 



In fig. 47 I have drawn the directions of the foregoing 

 muscles in the relative position which they occupy with 

 respect to the sphincter muscle. 



Fig. 47. 



The latter muscle is represented by the ellipse, whose foci 

 are 0 and (/ ; on the left-hand side of the ellipse are shown 

 the directions of the outer layer of radiating muscles, and 



