Nos. IAXD2.] AX ATOMY OF SCOMBER SCOMBER. 285 



. to the obliquus ventralis of its arch, and then toward the basal 

 line. The other branch reaches the ventral surface of the obliquus 

 ventralis, sends a branch to that muscle, traverses the so-called 

 obliquus ventralis of the fourth arch, and then turns backward 

 along the mesial surface of the pharyngo-hyoideus muscle near 

 its insertion. It apparently innervates both this muscle and the 

 obliquus of the fourth arch but this could not be definitely de- 

 termined. 



From the main truncus of the nervus, just as it separates into 

 its three portions, or even from the base of the pharyngeal branch 

 of the nervus, a large branch is sent downward and mesially to 

 the dorsal surface of the obliquus dorsalis of the third arch. 

 There it breaks up into several branches, some of which turn 

 mesially and forward, and others mesially and backward, along 

 the dorsal surface of the muscle. Certain of the posterior branches 

 enter the obliquus of the third arch, and others the transversus 

 dorsalis posterior. The anterior branches run forward onto the 

 obliquus of the second arch and onto the anterior division of the 

 transversus dorsalis, certain of them entering those muscles, and 

 others going to the general tissues of the region. As this nerve 

 apparently innervates all the muscles to which its branches are 

 distributed, it is evident that it must either contain, not only ele- 

 ments that belong to the second vagus, but also elements belong- 

 ing to the first vagus, or that the muscles that it innervates must 

 all belong to the third arch. As the latter supposition seems the 

 less probable, it must be that certain motor fibers belonging to the 

 first vagus are carried to the second vagus in that branch, found 

 by Dr. Dewitz, that goes to this last nerve from the large bundle 

 of fibers that passes ventral to the gangHa of the several nerves 

 without entering them. This branch of the bundle separates into 

 two parts as it fuses with the second vagus, one branch going to 

 the posttrematic branch of the nervus and one toward the base 

 of the branch here under consideration.* 



Close to the origin of this motor branch of the second vagus, 

 but either from the pretrematic branch of the nervus, or from the 

 united pretrematic and pharyngeal nerves, a separate branch is sent 

 to the external levator of the third arch ; and slightly distal to it 

 another branch to the interarcualis dorsalis that connects the 

 second and third arches. 



