SYMPATHETIC NERVES OF THE EDENTATA. lOl 



with the left recarreni nerve (e) thereby. The latter iilso coiii- 

 inunicates wth the lower cardific branch of the left vagus. But 

 no direct branch runs between the two recurrent nerves. 



The Ckcrdiac Nerves (f) : — The left vagus gives two fine nerves 

 to the superficial cardiac plexus (S.O.P), wherein they communi- 

 cate with the cardiac branch from the inferior cervical ganglion 

 of the left sympathetic. But no ganglia are found in connection 

 with them. The right vagus gives two large and two fine filaments 

 to the deep cardiac plexus (D.C.P), and fine filaments to the 

 superficial one. Reddish-brown ganglia are connected to the 

 nerves. There are no upper or middle cervical cardiac nerves. 



The pulmonary nerves (g) come from the vagus on the left 

 side, and from the vagus and deep cardiac plexus on the right. 



In the posterior part of the thorax branches are given ofi" to the 

 oesophagus and aorta, and the cesophageal plexus (O.P) is a link 

 between the vagi, for there are no dii'ect branches connecting 

 them. And the main cords run through the diaphragm on the 

 sides of the (esophagus. 



Abdominal Parts of the Vagi : — The left vagus I'uns along the 

 ventral surface of the stomach close to the lesser curvatuie. 

 The right one crosses behind the oesophagus and breaks up into 

 a numbei' of filaments. These reunite and the vagus ends in the 

 right part of the coeliac plexus. Several gastric nerves [J) run 

 to the dorsal aspect of the stomach, and communicating twigs 

 run to the hepatic (^) and splenic (k) plexuses. 



I did not observe any communications between the vagus and 

 phrenic nerves ; but fibres may get from the vagus into the 

 phrenic sympathetic plexus and be carried up to the diaphragm 

 to anastomose with the phi'enic nerve. 



The Cervical Sympathetic : — The superior and middle cervical 

 ganglia are absent, but the inferior cervical ganglia (I.C.G) are 

 large and round. They give ofi" the cardiac nerves (c.b.s), 

 thymic branches (t.b), subclavian (S.Y.B) and phrenic commu- 

 nicating (c.p.n) nerves. The left cardiac nerve ends in the 

 superficial cardiac plexus. The i^ight cardiac branch ends in the 

 deep plexus. The right sympathetic communicates with the 

 superficial cardiac plexus and left recurrent nerve. 



The Cardiac Plexus surrounds the aorta and its branches, 

 supplies them and the heart, and gives twigs to the right 

 pulmonary plexuses. It consists of superficial (S.C.P) and deep 

 (D.C.P) parts. The former lies on the ventral surface of the 

 aortic arch. It receives branches from both inferior cervical 

 ganglia, two branches from the left vagus, and twigs from both 

 recurrent nerves. The latter lies between the aortic arch and 

 innominate artery ventrally, and the trachea dorsally, and it 

 contains three reddish-brown ganglia (O.P.G). It receives 

 fibres from the right inferior cervical ganglion, and four branches 

 from the right vagus. Branches are given off to the trachea (t.p), 

 heart, and right lung. Both plexuses communicate by fine 

 nerves. 



