278 THE RABBIT 



(iii) The depressor nerve to the heart, passing backwards over 

 the cervical sjTiipathetic cord and continuing close to it and 

 alongside the common carotid artery. 



(iv) The inferior or recurrent laryngeal. At the posterior end of 

 the neck the right vagus gives off the inferior or recurrent 

 laryngeal nerve just where it passes over the right subclavian 

 artery. This recurrent laryngeal then passes under the sub- 

 clavian artery and proceeds along the side of the trachea to 

 the larynx. The vagus of the left side also gives off a re- 

 current- laryngeal, but it arises where the ductus arteriosus 

 joins the aorta, and it passes under the ductus arteriosus, 

 then along the side of the trachea to the larynx. 



(c) The spinal accessory or eleventh cranial nerves, beside the hypoglossals. 



(d) The hypoglossal or twelfth cranial nerves, each curving forwards round 



the angle of the jaw. 



(e) The spinal nerves (arising from the spinal cord), of which the third pair 



give rise each to a great auricular branch to the ear, and the fourth and 

 fifth pairs give off branches which join to form the phrenic nerves. 

 Each phrenic nerve passes backwards under the precaval vein and over 

 the subclavian artery of each side, and supplies the diaphragm. In 

 the thorax the phrenic nerves may be followed out between the heart 

 and the lungs. 



E. The Sub-maxillary Salivary Glands. 



There is a pair of these, glands situated one at either end of the lower 

 jaw, and in front of the larynx. Each is a compact reddish ovoid body, and 

 its duct (Wharton's duct) passes forward along the inner side of the jaw to 

 open into the floor of the mouth a short distance behind the lower incisors. 



F. The Blood-vessels. 



On either side of the trachea are the following vessels : — 



{a) The common carotid artery, along the outer side of the trachea. It 

 divides into an internal carotid artery, just posterior to the larynx, 

 and an external carotid, which continues alongside the trachea to the 

 side of the head. 



(b) The internal jugular vein from the brain. It runs alongside the vagus 



nerve, and joins the external jugular near the union of that vein with 

 the subclavian. 



(c) The external jugular vein, along the side of the neck. It is formed by 



the union of the anterior and the posterior facial veins. 

 Make a complete sketch showing the above parts, A-F. {See Fig. 93, 

 page 280.) 



The Solar Plexus. 



Turn the stomach over to the right side and note the folloAving parts : — 

 Arising from the last thoracic ganglion of either side is the splanchnic nerve. 

 Each splanchnic nerve passes backwards next to the aorta. Just over the 

 origin of the anterior mesenteric artery these nerves unite into a group of coeliac 



