590 THE ABTERIES. 



The single trunk which results from their anastomoses is placed, im- 

 mediately after its exit from the incisive foramen, directly beneath the 

 buccal mucous membrane, and at once divides into two principal branches 

 a right and left ; these are lodged in the tissue of the upper lip, and pass 

 back to meet the coronary arteries, with which they anastomose by inoscula- 

 tion, after throwing off on their track a great number of branches destined 

 to the muscles and integuments of the lip and nostrils. 



DIFFERENTIAL CHARACTERS IN THE CAROTID ARTERIES OF OTHER THAN SOLIPED ANIMALS. 



1. The Carotid Arteries in Carnivora. 



In the Dog, the carotids arise singly from the brachio-cephalic trunk, and ascend 

 beneath the transverse process of ttie atlas, along the trachea, following a course 

 exactly like that pursued by these vessels in the Horse. 



Among the collateral branches furnished by them, may be distinguished the thyro- 

 laryngeal artery, remarkable for its enormous calibre, its descending in front of the 

 lateral lobe of the thyroid gland, and its termination in the median isthmus of that 

 gland. 



The terminal branches of the carotid are, as in Solipeds: 1, The occipital; 2, The 

 internal carotid ; 3, The external carotid, the continuation of the primitive vessel. 



OCCIPITAL ARTERY. Inconsiderable in volume, this vessel arises in front of the 

 anterior border of the transverse process of the atlas, passes into the notch on its 

 border, and divides into two branches the occipito-muscular and the cerebro-spmal 

 arteries. 



In its course, it gives off branches analogous to those which emanate from the pre- 

 vertebral artery of the Horse. It also gives a mastoid artery, which only sends one very 

 small branch into the par ieto- temporal canal, and is destined almost exclusively to the 

 deep muscles of the neck. In addition, the occipital throws off a retrograde artery, which 

 directly joins the vertebral. 



The arrangement of the occipital artery in Carnivora is, therefore, almost identical 

 with what has been described in Solipeds. 



INTERNAL CAROTID ARTERY. This vesse 1 reaches the posterior opening of the carotid 

 canal, along which it passes forward, then describes a very curious flexure which leaves 

 the cranium by the carotid foramen (see page 62), then re-enters that cavity after 

 receiving a particular branch from the external carotid. It afterwards anastomoses on 

 the side of the pituitary fossa, with the divisions of the spheno-spirious artery and the 

 returning branches of the ophthalmic artery, forming a kind of plexus, which appears to 

 be a trace of the re'seau admirable of Ruminants and Pachyderms, and from which 

 proceed the cerebral arteries. 



EXTERNAL CAROTID ARTERY. This arterial branch terminates, as in Solipeds, 

 the superficial temporal and the internal maxillary arteries. 



It gives off on its course : 1. An artery representing the meningeal branch of tl 

 prevertebral of the Horse, and which ascends in a flexuous manner on the side of " 

 pharynx to join the carotid flexure. 



2. A laryngeal artery, entering the larynx with the superior nerve of that orgai 

 after giving ramuscules to the maxillary gland. 



3. The lingual artery, a very large tortuous branch, whose course resembles that of the 

 same vessel in the Horse. 



4. A facial or external maxillary artery, divided into two branches above the inferior 

 insertion of the digastricus. One of these branches, analogous perhaps to the submental 

 of Man, passes within this insertion, and is prolonged to the chin, after furnishing 

 ramuscules to the parts lodged in the intermaxillary space. The other branch winds 

 round the inferior border of the maxilla, in front of the masseter muscle, and is expended 

 on the face by ascending and descending branches, among which we can readily perceive 

 the two coronary arteries, and the two twigs which we have noticed in Solipeds as 

 terminal branches of the vessel. 



5. The posterior auricular artery, after detaching parotideal and musculo-cutaneous 

 vessels, is situated on the middle of the external face of the concha, and is directed 

 towards the terminal extremity of the cartilage, where it separates into two branches, 

 which are inflected en arcade, and return, in following the borders of the concha, towards 

 the base of the latter, where they anastomose with other branches, either from the pos- 

 terior or anterior auricular, and which come to meet them. 



