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The retina has elongated photosensitive rods but no cones (except in Mustelus and a few others), so that colour vision is lacking.

Posteriority the retina has a non-pigmented area centralis having rods where most acute vision occurs.

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The iris has poorly developed circular and radial muscles which can make the pupil a narrow slit.

The lens is very hard and round, it pushes the iris forwards almost touching the cornea. The ciliary body has no intrinsic muscles, and a dorsal suspensory liga­ment forms a gelatinous membrane or zonule attached to the ciliary body and the equator of the lens.

One the ventral side of the lens the gelatinous membrane has a small protractor lentis muscle which can swing the lens forwards in accommodation for near vision.

Eyelids are small, stiff folds of the skin, only the lower eyelid is slightly movable, the eye has no glands.

The fish is colour blind and the eye cannot discriminate minute details, but the eye is adapted for near vision in dim light and the animal can see its prey or predator.

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