138 The Allk^ator and Its Allies 



'23 



agus, and trachea; (3) goes to the oesophagus; (4) 

 goes to the heart, lungs, and stomach. 



XI. The spinal accessory nerve. There seems 

 to be some doubt as to the exact identity and 

 distribution of this nerve, but Bronn says that, 

 according to Fischer, it gives twigs to the lower 

 head-muscles and then divides into fine branches 

 in the atlanti-mastoideus muscle. 



XII. The hypoglossal nerve, going to the region 

 of the tongue, divides into three branches: (i) the 

 median and smallest goes to the sterno-maxillary 

 muscle; (2) the inner and larger goes to the same 

 muscle and also to the coraco-hyoid and sterno- 

 hyoid muscles ; (3) the outer and largest divides in- 

 to three twigs of which the first two lead to the 

 hyomaxillary and sterno-maxillary muscles respec- 

 tively, while the third divides into two twigs that 

 lead to the hyoglossal and genioglossal muscles 

 respectively. 



The Spinal Nerves 



x\s was noted above, the dorsal roots of the first 

 two spinal nerves are lacking. 



I, II, and III. The ventral branches of these 

 three nerves supply the smaller, ventral neck 

 muscles. 



IV. The ventral branch of this nerve innervates 

 with its chief divisions the ventral muscles, the 

 sphincter colli, and the integument of the neck, 



