272 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



off a branch below which follows the R. mandibularis 

 externus vii. 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 vii. 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 Faciali s — VII. 



The dorsal lateral line root splits to form the first 

 five of the following branches : — 



1. R. lateralis recurrens facialis (I. rec. vii.). — 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 



