90 AVES. 



with the prolongation accompanying the vertebral, at the bottom of the neck it clips 

 down in the median line between the anterior cervical muscles and divides into two 

 branches, each joining the last cervical ganglion but one of the sympathetic. After 

 it has communicated with several of the cerebral nerves, it is continued down the 

 spine in a canal with the vertebral artery, resembling the prolongation in the imperfect 

 canal in the snake, and the cord sent from the first thoracic ganglion and placed at 

 the side of the neck in the turtle, and that accompanying the vertebral artery in 

 mammalia. It adheres to the anterior trunk of each cervical nerve through a ganglion, 

 and thus forms a peculiar mode of communication. Having reached the thorax, its 

 ganglia are connected with those of the dorsal nerves, thus resembling, in a consi- 

 derable degree, the same in the turtle ; in the swan and pelican a large nerve may be 

 seen on each side proceeding from the first thoracic ganglion to communicate with the 

 pulmonary branches of the par vagum accompanying the large bloodvessels to the 

 heart ; the prolongation in the thorax is generally double, and becomes united at each 

 ganglion, and gives off an upper splanchnic nerve, and an inferior one as in the turtle, 

 which does not as in this animal form plexuses, or ganglia bearing any proportion to 

 the size of those in mammalia; the upper splanchnic nerve accompanies the creliac 

 artery to the gizzard and liver, and to communicate with branches of the par vagum, 

 and the inferior one is intimately combined with the renal capsule, and this in a 

 remarkable manner with the ovary ; it may therefore be a question whether the renal 

 capsules are in any way concerned in reproduction ; branches are given off which 

 follow the ramifications of the mesenteric artery to the intestines ; the prolongation 

 in passing down the spine sends branches on the meso-colon to communicate with 

 those of the inferior mesenteric plexus ; also branches to the kidney, and others to 

 communicate with the long branches of the spinal nerves destined for the cloaca and 

 adjoining parts, and thus form a plexus corresponding in some degree with that in 

 mammalia produced by the junction of the hypogastric plexus with branches of two 

 or three of the sacral nerves. 



The accompanying arteries of the thoracic portion of the sympathetic are two-fold 

 like the double prolongation, one being derived from the aorta in the same manner as 



