172 MAMMALIA. 



arch of the aorta and sends some filaments to join others from the left trunk of the par 

 vagum and pass on the posterior part of the pulmonary artery, with the right coronary 

 artery, to the right ventricle ; it then passes to the front of the pulmonary artery, with 

 the left coronary artery, to the left ventricle. From the first thoracic ganglion small 

 branches are sent along the superior vena cava to the right auricle. From the trunk 

 of the par vagum a branch is sent to the right auricle. On the left side a branch is 

 sent from the second cervical ganglion, it communicates with the recurrent, and 

 terminates principally on the aorta and pulmonary artery. Small branches, as on the 

 right side, are sent from the first thoracic ganglion to the pericardium and left auricle, 

 but some reach the left ventricle. The left trunk of the par vagum gives off a branch 

 which sends filaments to the aorta and pulmonary artery, and to join filaments from the 

 first cardiac nerve of the right side ; another branch is sent off by the left trunk of the 

 par vagum to the pulmonary artery and left auricle. 



The subclavian, or other large artery arising from it, and giving off the vertebral, 

 is generally embraced by branches passing from the inferior cervical to the first 

 thoracic ganglion, and one or more branches are always sent up from one or both of 

 these ganglia along with, and giving filaments to, the vertebral artery, and forming in 

 many instances the only communication with the cervical nerves ; but there is not a 

 ganglion at each point of union, as in birds. In mammalia, the small proportion of 

 the communicating branches of the sympathetic to the cervical nerves is very remark- 

 able, when compared with those connected with the dorsal. The thoracic portion of 

 the sympathetic supplies nearly the same parts as in man ; in the jaguar, branches 

 from several of the thoracic ganglia of the right side unite and communicate with the 

 right posterior pulmonary plexus, and then cross the spine to receive similar branches 

 from the thoracic ganglia of the left side, after their communication with the left 

 posterior pulmonary plexus ; thus a great resemblance to the thoracic plexuses in man 

 is formed. In the calf, a similar plexus gives off the more inferior cardiac nerves to 

 the left auricle and ventricle ; it proceeds from four or five of the thoracic ganglia on 

 the right side, and forms communications with the anterior cord of the par vagum, 

 which sends branches to the lungs before it descends to the stomach ; branches extend 



