Job 41:18

The animal is said to inflate itself, as it lies basking in the sun, and then force the heated breath through its nostrils, which in the sun appears like a stream of light.

the eyelids of the morning The reference may be to the shining of the reddish eyes of the animal, which are seen even under the water, before its head comes to the surface. In the Egyptian hieroglyphs the eyes of the crocodile are a symbol of the dawn.