I.] I.] THE FROG. 107 



the 5th and 7th, and passing behind the auditory 

 capsule, much as do the 5th and 7th in front of 

 it. 

 o. The xoth or pneumogastric (vagus); its cut 

 end will alone be seen. Soon after leaving the 

 skull it bears a large ganglion (g. trunci vagi). 

 /?. The cjth or glossopharyngeal ; it arises im- 

 mediately in front of a, and is largely con- 

 fluent with the above-named ganglion. It 

 is commissurally connected with the posterior 

 branch of the 7th (commissura ad facialeni). 

 Its distribution has been studied (§ i. a). 



g. The 8th or auditory ; arising from the medulla 

 along with the 7 th, part of which it appears 

 to be. Dissect to its level and trace it into the 

 auditory capsule. 



5. The sympathetic system. 



Dissect from the ventral aspect as before, but 

 leave the aorta, the cut end of the cceliaco-me- 

 senteric artery and the base of the large intestine 

 with the bladder, in place. On raising the aorta 

 the sympathetic will be found immediately beneath 

 (dorsal to) it. 



a. The main trunk of the sympathetic ; paired and 

 longitudinal, accompanying the arches and trunk 

 of the aorta. 



b. The splanchnic nerve ; arising from a at the point 

 of junction of the aortic arches and accompanying 

 the cceliaco-mesenteric artery. 



c. The sympathetic ganglia; enlargements on a, vari- 

 able in size and number; usually one for each 



