The cranial nerves of Wallago attu

Sinha, B. M.

The olfactory nerve supplies the front 1/2 of rosette by its 2 branches. The posterior 1/2 of rosette is innervated by fine branches from the olfactory lobe. The eye muscle nerves are very thin owing to the eyes being reduced. The superior branch of oculomotor nerve supplies the superior rectus muscle, while the inferior branch innervates the anterior rectus, inferior rectus and inferior oblique muscles. The trigeminal and facial nerves join intra-cranially into the trigeminofacial complex. The supraorbital trunk is well formed and the ramus ophthalmicus superficialis facialis innervates the supraorbital canal of lateral-line system. The infraorbital trunk is small and gives the ramus palatinus anterior to the palate. The ramus maxillaris innervates the maxillary barbel and the ramus buccalis supplies the sense organs on this barbel. The externus and internus branches of the mandibularis trigeminalis enter the lower jaw. The hyomandibular trunk gives off the ramus opercularis to the operculum and ramus palatinus posterior to the palate. Its mandibularis facialis branch innervates the mandibular canal of lateral-line system. The ramus lateralis accesorius receives the dorsal rami of spinal nerves. The vestibular branch of auditory nerve supplies the utriculus and ampullae of the semicircular canal, while the saccular branch is distributed to the cassulus, lagena and sinus endolymphaticus. The ganglion of glossopharyngeal nerve is extra-cranial. It innervates the first gill. The ganglion of vagus nerve is intra cranial. The fourth branchialis branch supplies the fourth gill and hind wall of branchial cavity. The anterior branch of visceralis innervates the heart, while the posterior branch supplies the viscera. The lateralis arises separately from the vagus and supplies the lateral-line canal.