HO ELEMENTARY BIOLOGY. [CHAE 



8. The recurrent laryngeal ; a long nerve arising in 

 front of and above a — y and coursing round the 

 base of the pulmonary aortic arch to reach the 

 larynx. 



The dorsal ramus ; arising from the main trunk 

 immediately after it leaves the skull, and dis- 

 tributed to the adjacent dorsal integument. 



e. Incidental. 



a. The course of the 5th and 7th (cf. § 4. ii. d. e. 

 et seq.). Remove the eye and the squamosal 

 and quadrato-jugal bones and follow the course 

 of the above nerves, as seen from the side. 



Note especially the relations of the 5th to the 

 mouth-cavity and of the 7 th to the tympano- 

 Eustachian passage (Eustachian recess). See 

 pp. 28, 29. 



/?. The sympathetic. Note especially the further 

 course of the splanchnic nerve (§ 5. ^8). It 

 bears a large ganglion in close proximity with 

 the cceliaco-mesenteric artery; add a little acetic 

 acid ; offshoots will be found to proceed from it 

 to the alimentary canal, accompanying, at their 

 outset, the branches of the artery. 



L. The anatomy of the sense organs. 



1. The gustatory organ. 



The shape and arrangement of the tongue have 

 already been described (Sect. E. § 1 d.). Snip off a 

 bit of mucous membrane from the upper surface of 

 the tongue of a recently killed frog, mount in salt 

 solution and cover in plenty of the fluid with a large 

 coverslip : examine with one inch obj. 



