Changes

*The eye glands of many reptiles are excretory organs for salt.

*The eye glands of many reptiles are excretory organs for salt.

*Some chelonians (for example, tortoise, turtle or terrapin) do not have eye glands.

*Some chelonians (for example, tortoise, turtle or terrapin) do not have eye glands.

*Some reptiles have what is termed a parietal eye, sometimes called their third eye. Although it is called an eye, the reptiles cannot actually see out of it, although it can be used to detect light and dark, meaning that is is photoreceptive. It is part of the epithalamus, and is associated with the pineal gland. It can be used to determine circadian rhythms. Circadian rhythms are the cycle of light and dark - these cycles have a big impact on feeding and sleeping habits, and they also have an impact on thermoregulation.

*Some reptiles have what is termed a [[Lizard Eye#Parietal Eye|parietal eye]], sometimes called their third eye. Although it is called an eye, the reptiles cannot actually see out of it, although it can be used to detect light and dark, meaning that is is photoreceptive. It is part of the epithalamus, and is associated with the pineal gland. It can be used to determine circadian rhythms. Circadian rhythms are the cycle of light and dark - these cycles have a big impact on feeding and sleeping habits, and they also have an impact on thermoregulation.

===Fish===

===Fish===