MYOLOGY 



235 



This muscle determines the narrowing and closure of the 

 palpebral orifice. 



Pyramidalis Nasi. — The pyramidal muscle is not found 

 in the domestic animals. It appears to be blended with 

 the internal elevator of the upper Up and wing of the nose ; 

 this is easy of comprehension if we bear in mind the relative 

 position of these two muscles in the human species. 



, 16 n 



Fig. 90. — Myology of the Dog : Muscles of the Head. 



I, Masseter ; 2, orbicularis palpebrarum ; 3, zygomaticus major; 4, lachry- 

 mal (this muscle is sometimes described under the name of the small 

 zygomatic) ; 5, levator labii superioris proprius ; 6, levator labii superioris 

 alaeque nasi; 7, caninus ; 9, buccinator; 11, zygomatico-auricularis ; 

 12, external temporo-auricularis ; 14, parotid gland; 15, parotido-auri- 

 cularis ; 16, inferior maxillary bone ; 17, digastric. 



Corrugator Supercilii. — This muscle is represented by 

 the fronto-palpebral muscle noticed above, which is by some 

 Regarded as a vestige of the frontal. 



Zygomaticus Major (Fig. 90, 3 ; Figs, 91, 92). — This is 

 the zygomatic-lahial of veterinarians. This muscle is of an 

 elongated form, and has a ribbon-like aspect. 



In the dog and the cat it arises from the base of the pinna 

 of the ear, from the portion of this base which bears the 

 name of scutiform cartilage. (With regard to this cartilage, 

 see p. 242, Zygomatico-auricularis.) From this it is directed 



