Inner ear of scoliodon or Membranus labrynth

 Procedure. 

1. The internal ear of the membranous labyrinth lies in the auditor capsule just behind the orbit on either side. The auditory capsules are seen as bulgings on either side. 
2. Remove the skin over the auditory capsule. Careful observation shows ridges of anterior vertical, horizontal, and posterior vertical semicircular canals. 
3. The cartilage capsule can be gently broken by forceps. 
4. Take care not to injure the canals of the membranous labyrinth. 
5. Locate the vertical canals and proceed. 
6. The internal ear consists of the anterior vertical canal, posterior vertical canal, horizontal canal. ampullae of the anterior vertical canal, horizontal canal and posterior vertical canal, lagena cochlea, recesses utriculi, utriculus, and nerve supplies. 

The internal ear

It lies in the auditory capsule of the skull. It is useful for the maintenance of equilibrium. In the fish external and middle ears are absent. Internal eats covered by the cartilaginous labyrinth. Space is present between membranous and labyrinth is filled with perilymph.

 The membranous labyrinth shows laterally compressed sac. It is divided into utriculus and sacculus. At the end of the sacculus, lagena is present.

 The internal ear shows 3 semi circular canals.

1.  Anterior vertical semicircular canal.
2. Posterior vertical semicircular canal.
3. Horizontal semicircular canal.

 These semicircular canals end with ampullae.

 From the dorsal side of the internal ear duct arises. This is called saccus endolymphaticus. 

It opens out on the skin.

 In the ampullae sensory patches are present, they will be acoustic in nature, in the utriculus and sacculus  are present. They are mainly useful for the maintenance of balance. Thus the internal ear is useful for caring and maintenance of balance.