133 
sense organs (10 and 11) of the hyomandibular canal, and 
is then continued at first backwards and then sharply 
downwards towards the edge of the operculum, to supply 
the opercular line of pit organs. 
Below and before it bends forwards the Truncts 
hyomandibularis splits into two large nerves—(1) an upper 
one turning forwards, the R. mandibularis vii. (san. vii.), 
consisting of two components accompanying each other, a 
coarse fibred R. mandibularis externus vil. (man. eat. vii.) 
and a fine fibred R. mandibularis internus vil. (man. int. 
vev.), and (2) a R. hyoideus vu. (r. Ay.) passing straight 
downwards. 
9. R. hyoideus (7. /7.).—Consists of two components, 
a coarse motor and a fine-fibred general cutaneous—just as 
in Menidia, but differing from Gadus. As in Jfenidia 
the hyoideus below divides into anterior and posterior 
branches. Sense organ 9 of the hyomandibular canal is 
supplied from the hyoideus, but this bundle of lateral line 
fibres has previously been handed over to it from the 
external mandibular. 
As the R. mandibularis passes forwards it gives off 
branches to pit organs, especially one long branch above 
corresponding to Herrick’s nerve m. viz. 8. It may be 
mentioned that the two components forming the R. man- 
dibularis are each easily followed by the microscope. 
Below a large lateral line branch is given off which sup- 
plies sense organs 6, 7 and 8 of the hyomandibular canal. 
In front, the two components separate out, and thereafter 
pursue independent courses. 
10. R. mandibularis internus (man. znt. vii.) —A 
communis nerve, situated much below the externus. 
Passes sharply inwards to the visceral surface, and does not 
rejoin the externus again as in Menidia, and as is usual in 
Teleosts, with the exception of Cottus according to Stannius. 
