The Nervous System 137 



by different paths, to the inner skin of the 

 mouth; (b') the second twig divides into four 

 parts two leading to the mylohyoid muscle 

 and to the integument at the corner of the 

 mouth, one to the integumental glands at the 

 corner of the mouth, and one to the floor of 

 the mouth cavity. 



VI. The abducens nerve leads to the retractor 

 oculi muscle and to the muscle for the nictitating 

 membrane. 



VII. The facial nerve gives off three main 

 branches: (i) the first divides again into three 

 twigs (a) connecting with a branch of the trigemi- 

 nal nerve, (b) and (c) connecting with the trigem- 

 inal and also leading to the palate; (2) the second 

 branch divides into two twigs that connect with 

 the glossopharyngeal nerve; (3) the third branch 

 divides into two parts, a muscular twig, and the 

 chorda tympani. 



VIII. The auditory or acoustic nerve leads, of 

 course, to the sensory regions of the ear. 



IX. The glossopharyngeal nerve divides into 

 four main branches, as follows: (i) to the larynx, 

 (2) to the oesophagus, (3) to the hyomaxillary 

 and sterno-maxillary muscles, and (4) to the tongue. 

 There are also certain communicating twigs with 

 the facial and vagus nerves. 



X. The vagus or pneumogastric nerve gives 

 off four branches: (i) and (2) communicate with 

 each other and supply the pharynx, larynx, cesoph- 



