Brain and Cranial Nerves of Acanthias vulgaris. 185 
The Vagus, X, emerges laterally by one large bundle of roots and a small 
one, not shown in the figures, behind, the former being composed of a number 
of small roots with a large one in front (Fig. 4). Its branches are typical. 
The Lateral Line branch, after leaving the trunk, turns away from the surface 
and runs down between the muscles not far from the axial skeleton (Fig. 1). 
The Branchial branches are four in number and each forks over its gill-slit, 
the posterior branch being the larger. This post-trematic branch divides into 
two rami—an anterior to the upper angle of the cleft, and a posterior to its 
posterior wall; the pretrematic gives off a small branch to the pharyngeal 
wall and then continues its way to the anterior hemibranch of the cleft. 
The Visceral branch is that part of the main trunk which remains after the 
other branches have been given off; just before reaching the ccelom it 
divides into four, all of which, however, run on to the cesophagus and thence 
to the viscera. 
The Glossopharyngeal, IX, runs out from the Medulla at right angles to 
the surface for the first two or three millimetres, but then turns backward and 
traverses the Auditory capsule obliquely and parallel to the proximal portion 
of the vagus. As usual it swells out, at a considerable distance from its origin 
at the anterior end of the vagus root, to form a fusiform ganglion, beyond which 
it forks over the first gill-slit. 
The VIIIth, VIIth, and Vth complex emerges by one dorsal and a bundle 
of ventro-lateral roots. The Auditory, VIII, is the hindmost of this latter 
set: it is short and dorso-ventrally compressed. For details of its distribution 
and for a description of the whole sense organ I cannot do better than refer 
to Retzius, but it should be noticed that the otocyst is of medium size, and 
instead of containing one or perhaps two large otoliths it possesses numberless 
small cuboid crystals, like very fine sand. 
The rest of the complex consists of the dorsal root and three lateral ones 
just in front of the Auditory nerve, but bundles of fibres from the dorsal root 
come down and fuse with the lateral ones making the clear demonstration of the 
roots in relation to the VIIth and Vth nerves rather difficult. The result of 
these fusions, however, is that two trunks emerge from the cranium; one of 
which runs backwards and outwards, passing through the anterior portion of 
the Auditory capsule; and the other of which enters the orbit. 
The hinder of these two is the Hyomandibular branch of VII (VII Am.). 
It is a mixed nerve: like IX, it supphes a cleft, in this case the Spiracular, 
but in addition it contains fibres of the Lateralis system and serves the sense 
organs on the skin of the hyoid arch. Its pretrematic branch, which should 
pass in front of the spiracle out of the mandibular arch, is very small (Fig. 1), 
and the branch of it which corresponds to the pharyngeal branches of the vagus 
