44 AMPHIBIA. 



surface of the anterior cervical muscles ; it communicates at the upper part of the 

 neck with the cord in the usual canal of the vertebral artery, and then, passes to join 

 the coeliac plexus. There is a continuation of the sympathetic having numerous 

 ganglia in the usual canal of the vertebral artery. The ganglia do not adhere to the 

 spinal nerves as in birds, but send branches to them : they are not so large in pro- 

 portion to the spinal nerves as in birds. There are ganglia in the thoracic and lumbar 

 portions ; and th.e thoracic adhere very much to the spinal nerves. A strong branch 

 from the first thoracic ganglion, which corresponds with the lowest nerve entering the 

 axillary plexus, accompanies the right portion of the vein corresponding with the 

 superior cava, which is not in one trunk, but the subclavian and jugular of each side 

 form a separate one, which enters at the bottom of the pericardium ; it becomes mixed 

 with branches of the par vagum, and thus corresponds in some degree with the cardiac 

 nerves in birds ; but the heart has also a large supply from the par vagum, the 

 branches of which ramify considerably on the pericardium before they pierce it for 

 reaching the heart. The nerves pass behind and on the pericardium, to which they 

 adhere so firmly as to be with difficulty separated in their progress to the heart. 

 There is a large plexus formed from the superior thoracic ganglia for the liver. 

 Branches, proceeding from several thoracic ganglia, form a plexus about the renal 

 capsule, instead of a semilunar ganglion, and from this and the other lumbar portion 

 branches are given to the ovary and oviduct, also to the intestines. There is more 

 membrane in the plexus than in the turtle, and the branches are finer and softer, so 

 that although it approaches nearer, it does not reach to the state of a fleshy, or close 

 semilunar ganglion, and does not form so uniform a membranous surface as in the 

 porpoise, pig, and others, in which there is much membrane and not much of the 

 close fleshy ganglionic structure. 



The brain of amphibia differs from that of fishes externally, in the size and shape 

 of several parts. In the larger size of the anterior lobes, in which there is a capacious 

 ventricle, a prominence in this that may be compared with the striated body and a 

 choroid plexus, in not having any mammillary eminences. In having small thalami, 

 connected together in the turtle by a very tenacious commissure, but not placed as in 



