AVES. 



320 



(8), which receive tributary absorbents from the 

 surrounding muscles, and a large branch (9) 

 corresponding to the deep-seated femoral vessels. 



The iliac trunk (10) accompanies the great 

 femoral vein into the abdomen, which it enters 

 anterior to the origin of the pubis; it there 

 receives branches from the lateral parts of 

 the pelvis (11) and afterwards separates into 

 two divisions. 



The posterior division receives some lym- 

 phatics from the anterior lobes of the kidneys, 

 and those of the ovary or testicles; it com- 

 municates anteriorly with a branch from the 

 absorbents which surround the great mesenteric 

 artery, and posteriorly with large vesicular 

 plexuses or receptacles (12, 13) surrounding 

 the aorta and its branches, and which receives 

 the lymphatics from the renal plexus, and those 

 accompanying the arteria sacra media (14). 



The sacral or pelvic plexiform vesicles of 

 the lymph are described by Panizza in the 

 Goose as being two in number, situated in the 

 posterior region of the body, in the angle 

 between the tail and the thigh. Each vesicle 

 is little more than half an inch long and a 

 quarter of an inch broad, and is shaped some- 

 what like a kidney-bean. Panizza laid them 

 bare in several living Geese and punctured 

 them, upon which the lymph issued in con- 

 siderable quantity, and coagulated into a jelly 

 like the lymph from ordinary lymphatics. 

 Fluids thrown into the lymphatics leading to 

 the vesicles not only filled these cavities, but 

 passed from them into the veins. There are 

 analogous vesicles in the Reptiles, which are 

 endowed with a pulsatile power, and propel 

 their contents into the pelvic veins per saltum ; 

 but the recent researches of Miiller (Archiv. 

 fur Physiol. 1834, p. 300) show that the pelvic 

 lymphatic vesicles of Birds are not endowed 

 with a power of motion like that belonging to 

 those of Reptiles, he having satisfied himself, 

 by repeated examination of the living Goose, 

 that the alternate contraction and dilatation of 

 these vesicles in this animal, which Panizza 

 conceived to depend on an automatic power 

 within them, corresponds exactly with the 

 motions of respiration, and no longer continues 

 when they are interrupted.* 



The anterior division of the femoral lym- 

 phatic trunk (16) accompanies the aorta, upon 

 which it forms a plexus with the branch of 

 the opposite side, and with the intestinal ab- 

 sorbents (15). 



These vessels, which from the transparency 

 of their contents can scarcely be termed with 

 propriety ' lacteals/ commence from a plexi- 

 form continuous network situated between the 

 mucous and muscular coats of the intestine; 

 they are larger here than when they quit the 

 intestine to pass upon the mesentery. They 

 accompany the branches of the superior mesen- 

 teric artery, there being many absorbents for 

 one artery, which by their anastomoses form 

 plexuses surrounding the bloodvessels. Before 

 reaching the aorta, these absorbents commu- 

 nicate with the inferior or posterior division of 



* See Allen Thompson, in Edinb. Med. and 

 Surg. Journ. No. 125. 



the femoral trunk, and with the absorbents of 

 the ovary or testicles, after which they pass 

 upon the aorta (16, 17), where they receive 

 the lymphatics of the pancreas and duodenum, 

 and terminate by uniting around the coeliac 

 axis (18) with the lymphatics of the liver, the 

 proventriculus (c), the gizzard, and the spleen, 

 forming a considerable plexus, from which, 

 according to Lauth, it is by no means rare 

 to see branches passing to terminate in the 

 surrounding veins. 



The aortic plexus (19), which may be 

 regarded as analogous to the receptaculum 

 chyli, always gives origin to two thoracic 

 ducts (20, 20) of varying calibre, but often, 

 as in the Goose, exceeding a line in diameter. 

 They are situated at their origin behind the oeso- 

 phagus () and in front of the aorta (6) ; they 

 advance forwards, diverging slightly from each 

 other, pass over the lungs (ww), from which they 

 receive some lymphatics, and terminate seve- 

 rally, after being joined by the lymphatics of 

 the wing, in the jugular 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 re- 

 ceives 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 di- 

 ameter 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 lym- 

 phatic 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 dis- 

 cerned upon those which are situated between the 

 ramiofthelowerjaw. 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 lymphatics 

 communicate together, at the anterior and pos- 

 terior parts of the neck, by transverse or ob- 

 lique 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 tho- 

 racic duct. 



Vascular system. Heart. The heart in 

 Birds is divided, as in Mammals, into four 



