33 2 THE CIRCULATORY SYSTEM. 



gland situated close to the caudoventral surface of the tympanic 

 bulla, at the side of the pharynx. Thence a large lymphatic 

 trunk passes caudad at the side of the trachea, along with the 

 common carotid artery and internal jugular vein, unites with 

 the superficial vessels from the head, above described, joins 

 (on the left side) the thoracic duct, and enters the external 

 jugular vein. 



2. Lymphatics of the Neck. Two or three lymph-glands 

 are found in the fatty mass in the neck beneath the clavotrape- 

 zius and levator scapulae ventralis muscles. These receive 

 lymphatics from the neck and side of the thorax. The vessels 

 which arise from them join those from the head and arm to 

 enter the external jugular vein. 



3. Lymphatics of the Thoracic Limbs. The lymphatics 

 of the forelimbs begin as a number of vessels on the dorsum 

 and palm of the hand. These all pass toward the radial side, 

 and at about the base of the first metacarpal the vessels from 

 both sides of the hand unite to form two or three main trunks. 

 These pass towards the elbow, accompanying the vena cepha- 

 lica (Fig. i 30). There are usually two of these main trunks, 

 one lying on each side of the vena cephalica. They accompany 

 this vein over the shoulder, following that portion which finally 

 joins the external jugular. In the hollow of the shoulder they 

 enter the cervical lymph-glands, one or two lymph-glands 

 imbedded in the fat lying beneath the clavotrapezius and 

 levator scapulas ventralis in this region. From the cervical 

 lymph-glands a single trunk passes mediocaudad, unites with 

 the lymphatics from the head, and usually (on the left side) 

 with the cranial end of the thoracic duct, and enters the 

 external jugular vein at its junction with the subclavian. The 

 common trunk from the head and arm may enter the jugular 

 separately, but close to the termination of the thoracic duct. 

 On the right side the common trunk is joined by one or more 

 small vessels coming from the lymphatic glands of the thorax 

 and forming the right lymphatic duct. 



There is said to be also a deep system of lymphatics in the 

 arm, in addition to the superficial system above described; this 

 is said to accompany the branches of the brachial vein. If this 



