THE SKATE. 83 



branches to the vestibule and ampullae of the semicircular 

 canals (Fig. 28, n). 



218. The course of the ninth nerve through the capsule 

 (Fig. 22, IX ) : it enters the latter by an aperture in about 

 the middle of its anterior wall, passes backwards and out- 

 wards nearly parallel with the eighth and leaves the capsule 

 in its postero-external region by an aperture already noticed 

 in the skull (25). 



219. The course of the vagus through the auditory 

 capsule (Fig. 22, Jf): leaving the cranial cavity it passes 

 through a canal excavated in the postero-internal wall of the 

 capsule, the outer end of the canal being the vagus foramen 

 (see 24, 33). 



XLIX. Place the fish in the supine position, find the large 



sympathetic ganglion mentioned in 150, and trace back 

 220. The sympathetic nerve, which consists of a longitudinal cord 

 on each side of the vertebral column, presenting ganglia at intervals, 

 and connected by rami communicantes to the spinal nerves. As 

 already mentioned, the adrenals or supra-renal bodies are in intimate 

 connection with the sympathetic ganglia. 



L. Dissect away the kidneys and the peritoneum 

 from the dorsal wall of the abdominal cavity, 

 and note 



221. The spinal nerves, passing to the body walls and 

 fins : many of them converge, and exhibit a tendency to the 

 formation of plexuses. 



222. The lateral branch of the pneumogastric (Fig. 22, 

 X)i a longitudinal nerve, lying to the dorsal side of the 

 spinal nerves. 



LI. Make a longitudinal vertical section of a brain 

 hardened in spirit, and note 



223. The relations of the various divisions of the brain 

 already seen, and of the cavities they contain (Fig. 24) : the 



G 2 



