170 .MAMMALIA. 



principally accompanying the left coronary artery, and those with the left, the right. 

 In the calf, the prolongation passes to a very small ganglion from the trunk of the 

 par vagum, and from this nerve and the first thoracic ganglion the principal portion 

 of the superior cardiac nerves is sent off to the auricles and ventricles ; the inferior 

 cardiac nerves arise from the thoracic, and will be described further on. In the ass, 

 the sympathetic passes from the trunk of the par vagum nearly as in the calf, but the 

 right inferior cervical ganglion is rather larger, and the left extends to the first 

 thoracic ; distinct communications exist between branches from the first thoracic 

 ganglion, the phrenic nerve, and the trunk of the par vagum ; the inferior cervical and 

 first thoracic ganglia communicate very much with the recurrent nerves and some 

 branches of each trunk of the par vagum, so as to form a plexus, from which branches 

 proceed to the heart, those of the right side prevailing for the left ventricle, and those 

 of the left for the right ; others, joined by branches from the trunk of the par vagum, 

 are given to the auricles. In the jaguar, the sympathetic, on leaving the trunk of 

 the par vagum, passes to the inferior cervical ganglion, which on the right side forms 

 a small ganglion, and a still smaller one on the left ; these send off branches to encircle 

 the subclavian artery, and join the first thoracic ganglion, and give off cardiac branches, 

 which, together with others from the first thoracic ganglion and the trunk of the par 

 vagum on each side, form communications with the recurrent nerves : the branches 

 then pass principally to the ventricles ; other branches from the trunk of the par 

 vagum and recurrent, which have communicated with some of those given to the 

 ventricles, pass to the auricles, but some of these are also extended to the ventricles. 

 Branches from the first thoracic ganglion join the par vagum, the recurrent and 

 phrenic nerves. In the dog and fox, the inferior cervical ganglion is intimately 

 connected with the trunk of the par vagum ; it is placed at the inner side of the first 

 thoracic, the short prolongation passing from one to the other over and under the 

 subclavian artery, it sends off branches to join others from the thoracic ganglia, from 

 each trunk of the par vagum and the recurrent, for supplying the heart ; in the fox, 

 it appears almost as if a large branch issued from the first thoracic ganglion to join 

 the trunk of the par vagum, and for many of the cardiac nerves to pass off after this 



