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off a branch below which follows the R. mandibularis 
externus vil. for a bit, but ultimately separates out again. 
Some of the fibres of the R. mandibularis are distributed 
to the mucous surface, and hence probably represent a 
communis vil. component. 
Rami 2, 3 and 4 are known as the first, second and 
third divisions of the trigeminus, and hence its name. 
The profundus nerve, though associated with the 
trigeminus, may be a separate nerve altogether, and its 
relations with the fifth purely secondary. 
Nervus FPacialis—Vil 
The dorsal lateral line root splits to form the first 
five of the following branches :— 
1. R. lateralis recurrens facialis (/. rec. v2.) —This 
is the first branch to arise from the root, and is given off 
intracranially from the top of the ganglion. It soon gives 
off two twigs behind as shown in the chart, each of which 
enters the skull wall by a separate aperture. They unite 
in the skull wall, however, and after leaving it, pass back- 
wards to reinforce the posterior division of the R. oticus. 
The main trunk passes upwards and forwards between the 
optic lobe and the skull wall, perforates the frontal at the 
place marked with a ring in the chart, and is distributed 
to pit organs along its course. The R. lateralis acces- 
sorius (=R. lateralis trigemini) is, as pointed out by 
Stannius, absent in the Plaice, but the present nerve 
undoubtedly corresponds to the lateral line fibres which 
accompany it in the Cod, as described by Herrick. There 
are a very few fine fibres in it, which may conceivably be 
a vestigial R. lateralis accessorius, but the bulk of its fibres 
certainly belong to the lateral line series. 
A little distal to the origin of the above, and also 
intracranially from the top of the ganglion, at the place 
