312 



REPTILIA. 



suul 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 connexion is 

 so much greater than in the turtle ; but in this 

 creature the palate is horny, and not so extensive 

 in proportion to the size of the head. 3, pro- 

 longation 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 with the eleven superior spinal nerves ; 

 it emerges on each side at the place the superior 

 branches of the vertebral artery enter to distribute 

 branches in the intercostal spaces ; it is continued 

 downwards 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 be- 

 neath the membrane connecting the viscera with 

 the ribs and spine, and communicates with fila- 

 ments of the par vagum ; it is afterwards continued 

 downwards, receiving a filament from each spinal 

 nerve ; in its course it is a very fine nerve, and has 

 not any more ganglia than the first, and those com- 

 municating 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 be- 

 ginning of the intestine, where it resembles that 

 corresponding with the semilunar 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 dif- 

 ferent viscera. 4, second trunk of the fifth ; after 

 communicating with the sympathetic, and giving 

 filaments to the membrane of the mouth, palate, 

 and nose, it passes out of its canal in the upper jaw, 

 and terminates in branches on the upper lip. 5, 

 third trunk of the fifth ; it gives branches to the 

 muscles of the jaws, the greatest portion of it then 

 passes within a canal in the lower jaw ; it sends 

 three branches through the opening at the inferior 

 margin of this part, two of them to communicate 

 with the branches of the par vagum and ninth, dis- 

 tributed on the muscles and parts underneath the 

 jaw; the other to give filaments to the membrane 

 of the mouth as far as the sheath of the tongue : 

 the trunk is continued onwards through the fora- 

 men, near the chin, to divide into branches and 

 terminate on the lower lip. G, hard portion of the 

 seventh ; it communicates with the ganglion of the 

 sympathetic, and then passes through the digastric 

 muscle, to which it gives a branch; it communi- 

 cates with the first spinal nerve, and terminates on 

 the costomaxillary muscle. 7, glosso-pharyngeal 



Sympathetic System. The sympathetic sys- 

 tem of the tortoise is so feebly developed as 

 to be detected with difficulty, except in the 

 interior of the carapax, where nervous ganglia 

 are distinctly recognisable both in the peri- 

 toneal folds and on the bodies of the vertebras. 



The ganglia exactly resemble those of birds; 

 they give off two filaments superiorly and two 

 infcriorly : the latter pass beneath the trans- 

 verse process of the vertebrae, which is here 

 connected with the carapax. From the inner 

 margin of each ganglion a splanchnic nerve is 

 given off, which runs to assist in forming a 

 plexus, ramifications from which accompany 

 each of the arteries given off by the aorta, and 

 likewise assist in forming a pulmonary plexus. 

 The intercostal ganglia may be traced as 

 far as the sides of the first vertebra of the tail. 



Bojanus has represented the sympathetic 

 of the European tortoise (Eniys enroptra) as 



nerve ; it passes to the ganglion of the sympathetic. 

 8, trunk of the par vagum ; it communicates with 

 the sympathetic, and then with a branch that ap- 

 pears to be the continuation of the glosso-pharyngeal 

 from the ganglion of the sympathetic ; it sends a 

 branch to communicate with the ninth, to pass to 

 the muscles, &c., of the fauces ; and is then continued 

 downwards close to the trachea, in company with 

 each jugular vein ; on the left side it also ac- 

 companies the carotid artery, and from this a small 

 vessel also ascends with the right trunk ; it sends 

 filaments on the large vessels towards the heart, and 

 others behind each aorta, similar to the recurrent 

 nerves, to be distributed on the trachea and oeso- 

 phagus ; each trunk, for a short space, accompanies 

 its corresponding pulmonary artery : a little above 

 the liver it passes in front of the superior part of the 

 lungs, and proceeds a short distance, where it is 

 joined by its fellow to form a single nerve; this is 

 continued downwards under a thick membrane on 

 the liver, and appears to give filaments to this 

 viscus, the lungs, and oesophagus : about the termi- 

 nation of the liver it sends a large branch, which 

 has communicated freely with branches of the sym- 

 pathetic to the left surface of the stomach ; this 

 gives filaments to the lowest part of the lungs, and 

 terminates on the stomach. The right division, or 

 the continuation of the nerve itself, having com- 

 municated several times with the left division and 

 filaments from the plexus of the sympathetic, is 

 continued a short way on the membrane connecting 

 the viscera, it passes on the right surface of the 

 stomach, distributing branches to this viscus, and 

 terminates on the beginning of the intestine, reach- 

 ing as far as the pancreas. 9, a nerve from the 

 ganglion of the sympathetic ; it appears to be the 

 continuation of the glosso-pharyngeal after its 

 junction with the ganglion, it communicates with 

 the ninth after its connection with a branch of the 

 trunk of the par vagum, and terminates on the 

 glottis and muscles attached to the anterior point of 

 the jaw for drawing forward the trachea. 10, ninth 

 nerve ; it receives a branch from the trunk of the 

 par vagum, and from the hard portion of the 

 seventh ; after this has communicated with the first 

 cervical nerves, it gives off several branches to the 

 muscles of the tongue and throat, and one that 

 reaches to the end of the tongue, and one to com- 

 municate with branches of the third trunk of the 

 fifth, issuing out of the inferior part of the lower 

 jaw. The glosso-pharyngeal, the trunk of the par 

 vagum, and the ninth, are so connected together 

 that it is difficult to determine precisely to which 

 nerve each branch belongs ; they have been with 

 great care apportioned to their respective nerves in 

 this description. 



accompanying the carotid artery into the 

 cranium, and uniting with the vidian and the 

 facial nerves. On issuing from the cranium, 

 he describes it as being closely connected 

 with the vagus and with the glosso-pharyn- 

 geal nerves, so that it is difficult to say whe- 

 ther a superior cervical ganglion exists or not; 

 and as the cervical vertebra are here devoid of 

 the vertebral canal, the nerve is equally inse- 

 parably 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 dis- 

 tributed to the aorta, the cardiac plexus, and 

 the cceliac plexus. Between the seventh 

 and eighth cervical vertebra? is situated the 

 inferior cervical ganglion, which seems to be 

 merely an elongated swelling of the nerve ; 



