ABSORBENT SYSTEM OF BIRDS. 183 



vein of the same side. The left thoracic duct, before entering 

 the vein, receives the trunk of the lymphatics of the left side of 

 the neck ; the right thoracic duct receives only a branch of those 

 of the same side. 



The lymphatics of the wing follow the course of the brachial 

 artery, forming a plexus around it, especially at the elbow-joint. 

 Their principal trunk, to which all the collateral branches are 

 united about the upper third of the humerus, is here of large size, 

 but its diameter soon begins to be diminished, and it is very small 

 at the head of the humerus. When it reaches the parietes of the 

 chest, it receives two or three large lymphatics from the pectoral 

 muscles, and a branch which accompanies the brachial plexus. 

 Soon after a small lymphatic gland is sometimes formed on the 

 trunk, which lastly unites with the thoracic duct of its own side. 



The lymphatics of the head accompany the branches of the 

 jugular vein, and are readily discerned upon those which are 

 situated between the rami of the lower jaw. They form, by 

 uniting with the cervical absorbents, two lateral branches on each 

 side, which accompany the corresponding jugular vein, being- 

 situated, one in front, the other behind that vessel. These lym- 

 phatics communicate together, at the anterior and posterior parts 

 of the neck, by transverse or oblique branches. They receive in 

 their progress absorbents from the muscles, and from the peculiar 

 glands which are seen beneath the skin of the neck. The internal 

 branch on the left side receives also a considerable absorbent from 

 the oesophagus. At the lower part of the neck both branches 

 receive a notable branch which accompanies the carotid arteries, 

 and a little further on they form on each side a lymphatic gland 

 situated on the jugular vein. On the right side the trunk of the 

 cervical lymphatics terminates in the jugular vein, after having 

 furnished a communicating branch with the thoracic canal of that 

 side ; on the left side it terminates at once in the corresponding 

 thoracic duct. 



