242 Journal of Comparative Neurology. 



derived wholly from the caudal projection of the ganglion of 

 the first root of the vagus. 



The dorsal division of the r. lateralis superior {l.s.d.') aris- 

 es from the main nerve a short distance from the ganglion and 

 inclines slightly laterad and abruptly dorsad between the m. ex- 

 tensor dorsi communis and the m. cucullaris. Near the trans- 

 verse level of the axilla it begins to send fibers to the line of 

 sense organs of the dorsum. 



The main part of the r. lateralis superior follows a course 

 dorsally of, and approximately parallel with, the t. visceralis X, 

 but soon becomes separated from the later nerve by the m. basi- 

 scapularis. Dorsally of this muscle it continues caudad beyond 

 the suprascapula and innervates the sense organs of the lateral 

 line of the trunk. 



7. — The Trioiciis Visceralis Vagi. 



The t. visceralis {i^sc.^ passes out of the posterior extremity 

 of the ganglion IX+X. It is composed of lateralis fibers dor- 

 sally; of motor fibers from the fourth, and probably also from 

 the third, vagus root, ventrally; and of communis fibers in its 

 central portion. There is no evidence of general cutaneous 

 fibers in the trunk. The communis fibers are derived from the 

 third root of the vagus. It may be that the second root of the 

 vagus, also, sends some fibers into this trunk, since the latter 

 contains the equivalent of a typical branchial trunk minus the 

 fibers which would go to an external gill, and since the second 

 root of the vagus affords the corresponding components of the 

 two anterior branchial trunks of the vagus. 



The t. visceralis passes caudad and slightly ventrad until it 

 approaches the transverse level of the origin of the third spinal 

 nerve. Here it turns ventrad across the lateral aspect of the 

 pharynx and divides into three terminal branches. 



In its course caudad, the t. visceralis usually passes be- 

 tween the m. basi-scapularis and the m. cucullaris. In a speci- 

 men of A. punctatum two inches long, however, the entire 

 nerve inclines laterad and comes to lie on the lateral side of the 

 m. cucullaris, and laterally also of the anterior part of the m. 



