174 J. B. Johnston 
From 625 the bnndle which will form the second branchial 
nerve is separating from the ventral side of the vagus trunk. The 
facts that the ganglia in the trunk are limited to its ventral part 
and that the branchial nerves separate from the ventral side a short 
distance behind the ganglia seem to show that the ganglion in the 
trunk .belongs in each case to the following branchial nerve. The 
second branchial nerve also eontains a few ganglion cells after it 
leaves the trunk. At 657 it bends down, at 668 reaches the mucosa, 
at 675 gives off the ramus visceralis mesially. This goes mesially 
and forward along the base of the branchial lamellae in the caudal 
wall of the third sae and innervates five sense organs on the inner 
wall of the 3’ branchial arch (650). The organs, the position of 
the ramus and the behaviour of its fibers are just as in the case of 
the visceral ramus of IX. Although in the reconstruction in lateral 
view shown in the plate this ramus and its organs lie in front of 
the external gill opening, this deceptive appearance is due to the 
very oblique position of the gill sacs, as the horizontal reconstruction 
in Fig. 17 makes clear. 
The ramus musculo-cutaneous goes (670—685) down caudal to 
the gill opening, giving branches to the museles, and reaches the 
skin in exactly the same way as the ramus of the first branchial 
nerve. The component to the skin is general eutaneous. How the 
pit organs above the gill slit are innervated I have not seen. It is 
quite possible that neuromast fibers accompany some of the motor 
branches and then reach the sense organs. 
At 660 the vagus trunk receives the ventral ramus from the 
6th dorsal spinal nerve. The trunk contains a small ganglion in 
its ventral part which beyond 680 is eontinued as one or two cells 
in each section. At 697 the ventral ramus of the 7!" ventral spinal 
Joins the lateral surface of the vagus trunk and immediately a part 
or the whole of it goes off as a small ventral branch to the inner 
surface of the body museles. At 731 the ventral ramus of the 7 
dorsal spinal joins the vagus trunk, and at 760 the ventral ramus 
of the S!" ventral spinal. 
From 730 the third branchial nerve is slowly separating from 
the trunk, at 760 it goes ventro-laterally and contains ganglion cells, 
and at 778 reaches the mucosa. At 785 the ramus visceralis goes 
mesially and behaves exactly as that of the second branchial 
nerve, innervating five sense organs at about 745. The ramus 
musculo-cutaneous takes the same course as in previous cases, sup- 
