MUSCLES OF THE TRUNK. 289 



and the horizontal portion of tlie posterior border of the styloid bone. Its 

 fasciculi become longtT as they are situated posteriorly, are rather tendinous, and 

 are earned from one of these bones to the other. Outwardly, it responds to the 

 parotid gland ; inwardly, to the guttural pouch, which it covers for its whole 

 extent ; its posterior border is largely confounded with the suyx^rior insertion of 

 the digastricus. When this nuiscle acts, it causes the os hyoides to swing, carry- 

 ing its inferior extremity backwards and downwards. 



6. Hyoideus Transversus. 



By this name Bourgelat has described a short riband of parallel muscular 

 fibres, which unites the superior extremities of the styloid cornua, and approxi- 

 mates them to each other. 



Differential Characters of the Muscles of the Head in the other Animals. 



1. Facial Region. 



Ruminants. — There are found in the Ox : 



1. An orbicular muscle of the lips, analogous to that in the Horse. 



2. A buccinator of the same kintl (Fig. 172, 5). 



3. A zyfiomaticus, stronger and rediler than in Solipeds. Its aponeurosis of origin, covered 

 by the panniculus, extends upon the surface of the masseter muscle as far back as the zygo- 

 matic arch, to which it is attache 1 (Fig. 172, 7). 



4. A levator labii superioris alsequi nasi, continued, above, with the inferior border of the 

 frontal or fronto-cuticuluris musch^ ; and divided, inferiorly, into two branches, which comprise 

 between them tlie levator labii superioris and the dilator naris lateralis. These two branches, 

 however, are not disposed as in Solipeds, the anterior covering the preceding muscles, and the 

 posterior, of but little importance, passing beneath them to lose itself in the substance of the 

 upper lip (Fig. 172,3). 



5. A levator labii superioris proprius, which gains the middle of the muzzle by passing 

 along the inner side of the nostrils (Fig. 172, 1). 



6. Two additional levator labii superioris muscles to the above, considered as accessories to 

 the first, and which originate with it. Each terminates by a ramifying tendon that passes 

 und-^r the nostril to mix in the tissue of the upper lip (Fig. 172, 1', 1'). 



7. A dilator naris lateralis, situated between the supermaxillo-labialis and its two access^ory 

 muscles, and deriving its origin, in common with these three muscles, iu front of the maxillary 

 spine (Fig. 172, 2). 



8. A depressor labii inferioris, confounded with the buccinator, and having no terminal 

 tendon. 



9. A levator menti, attached to the body of the inferior maxillary bone, as in the Horse, 

 by two middle posterior muscles. No anterior middle muscle has been found by us ; and it is 

 certain that tlit-re is no dilator naris transversalis or dilator naris superioris present. 



In the Sheep, the levator labii superioris does not exist ; apart from this peculiarity, there 

 is no difference between the facial mu.-cles of this animal and the Ox. 



Pig. — This animal has no levator labii superioris, or dilator naris transversales muscle.s. The 

 dilator naris superior is present; it is bhort, very thick, and situated near the margin of the 

 nostrils. The levator labii superioris proprius and the dilator naris lateralis are re| laced by 

 three fleshy bodies, nearly parallel, lying on the side of tlie face. The superior originates in 

 the lachrymal fossa, and terminates by a tendon in the middle of the snout. The inferior, with 

 the middle, leaves the imprints in front of the zygomatic ridge, and is continued at its inferior 

 extremity by a tendon tlivided into several fibrillae, which pass below the nostril to be unit' d 

 to the tendon of the superior portion : this is done in such a manner that the external opening 

 of the nose is encircled on tiie inner side by a kind of fibrous cravat, which, when these two 

 niuscles contract, carries this opening outwards. It will also be understood that the superior 

 fleshy body, acting alone, ought to elevate the snout, while the inferior depresses it in drawing 

 it to one side. With regard to the intermediate fleshy mass, it is the representative of the 

 dilator nar/s lateralis of the Ox, and terminates in a great quantity of tendinous fibrillje at 

 the internal ala of the nose. 



Carnivora. — In the Dog and Cat the following peculiarities are found: — 



The orbicularis oris is quite rudimentary. 



