322 ANATOMY OF VERTEBRATES. 



and is distributed on the membrane covering the anterior part of 

 the mouth and palate. It is worthy of remark that the nerves 

 distributed on the membrane of the mouth and nose communicate 

 so many times with branches of the second trunk of the fifth, and 

 their connection is so much greater than in the Turtle ; but in 

 this creature the palate is horny, and not so extensive in propor- 

 tion to the size of the head. 3, prolongation of the sympathetic 

 connected with the trunk of the par vagum, but not directly with 

 the ganglion of the sympathetic ; it communicates with the ninth 

 nerve, then passes down the spine, and communicates Avith the 

 eleven superior spinal nerves ; it emerges on each side at the 

 place the superior branches of the vertebral artery enter to dis- 

 tribute branches in the intercostal spaces ; it is continued down- 

 wards in a very fine plexiform prolongation with the vertebral 

 artery, as far as the origin from the right aorta ; it then branches 

 to each side beneath the membrane connecting the viscera with 

 the ribs and spine, and communicates with filaments of the par 

 vagum ; it is afterwards continued downwards, receiving a fila- 

 ment from each spinal nerve ; in its course it is a very fine nerve, 

 and has not any more ganglia than the first, and those communi- 

 cating with the second trunk of the fifth ; but at different points 

 from which the nerves pass to the viscera, there is an appearance 

 of a delicate plexus : this plexiform structure varies in different 

 parts, and becomes much greater about the beginning of the 

 intestine, where it resembles that corresponding with the semi- 

 lunar ganglion in the Turtle : near the kidney it assumes the 

 form of a nervous membrane or retina, before it is distributed on 

 the urinary and generative organs. Branches pass from the 

 plexuses with the arteries to the different viscera.' ' 



Bojanus describes the sympathetic nerve of the Emys Eurojxza 

 as accompanying the carotid artery into the cranium, and uniting 

 with the vidian and the facial nerves. On issuing from the 

 cranium it is closely connected with the vagus and with the 

 glosso-pharyngeal nerves, so that it is difficult to say whether a 

 superior cervical ganglion exists or not ; and as the cervical 

 vertebrae are ribless, there is no ' vertebral canal,' and the nerve 

 is closely connected with the vagus throughout the whole length 

 of the neck. Below the sixth cervical vertebra the sympathetic 

 nerve separates itself from the sheath of the vagus, and becomes 

 connected with a middle cervical ganglion, whence issue filaments 

 that are distributed to the aorta, the cardiac plexus, and the coeliac 

 plexus. Between the seventh and eighth cervical vertebra? is 

 situated the inferior cervical ganglion, like an elongated swelling 



] xliv. p. cr>. 



