200 NERVE COMPONENTS OF BONY FISHES. 



trunk now continues forward in its former position ven- 

 trally of the supra-orbital canal and separated from it by 

 the nasal bone. Mesally of it is the internasal cartilagfe, 

 laterally the nasal sac and ventrally the olfactory nerve. 



Under the caudal end of the nasal bone several twigs 

 are given off, one of fine fibres mesally for the skin (not 

 figured), one laterally of fine and medium fibres [so. 12), 

 and two dorsally {so. ij and so. /^), each of coarse and 

 medium fibres, leaving in the main trunk only very fine 

 fibres with a few coarse ones scattered among them, the 

 typical general cutaneous arrangement. One of the dor- 

 sal twigs {so. ij) supplies the first canal organ ; the other 

 {so. 14) and the lateral twig {so. 12) turn laterad along the 

 dorsal wall of the nasal sac, anastomose with each other, 

 and terminate in three large naked sense organs {g^ h, i) 

 between the dorsal margin of the anterior nasal aperture 

 and the cephalic end of the supra-orbital canal. This 

 arrangement was confirmed on the opposite side of this 

 specimen and the three organs were seen in other 

 sections and in surface preparations of the skin of this 

 region. 



From the trunk other cutaneous twigs directed inward 

 go off from time to time and under the first canal organ it 

 receives the anastomosing branch from the infra-orbital 

 trunk. The latter passes between two separated bundles of 

 fibres of the supra-orbital trunk to the naked sense organs 

 d, e, /", above the maxillary bone, as already described. 

 It is possible that some fibres from the infra-orbital trunk 

 remain in the supra-orbital trunk, but certainly no con- 

 siderable number do so. 



After the anastomosis the fibres of the trunk distribute 

 to the skin of the top of the snout to the extreme tip of 

 the upper lip. Near the end of the premaxillary bone a 



