182 ANATOMY OE VERTEBKATES. 



cles ; it communicates anteriorly "vvith 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 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 

 somewhat like a kidney-bean in the Goose. ^ They have muscular 

 coats with striated fibre, distinctly recognisable in those of the 

 Ostrich, where these ^lymph-hearts' are attached to the con- 

 tiguous bone. In the Cassowary, Stork, and Goose, they lie free. 

 The pulsations correspond with the motions of respiration. 



The anterior division of the femoral lymphatic trunk, 16, accom- 

 panies the aorta, upon which it forms a plexus with the branch of 

 the opposite side, and with the intestinal absorbents, 15. These 

 vessels commence from a plexiform 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 

 mesenteric artery, there being many absorbents for one artery, 

 which by their anastomoses form plexuses surrounding the blood- 

 vessels. Before reaching the aorta, the lacteals communicate 

 with the inferior or posterior division of the femoral trunk, and 

 mth 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 proventri- 

 culus, 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 answers to the ' receptaculum 

 chyli ' of Mammals, 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, a, and in front of the aorta, b ; they advance forward, 

 diverging slightly from each other, pass over the lungs, w, w, from 

 which they receive some lymphatics, and terminate respectively, 

 after being joined by the lymphatics of the wing, in the jugular 



^ XLir, tab. ix. fig. 3. 2 ^li-. p. 381. 



