The dark blue, teal, and gold<unk>  from the eye of a cow Retina of mongrel dog with strong tapetal reflex The<unk>  (; ; ) is a layer of tissue in the eye of many vertebrates. Laying immediately behind the retina, it is a retroreflector. It reflects visible light back through the retina, increasing the light available to the photoreceptors (although slightly blurring the image). The<unk>  contributes to the superior night vision of some animals. Many of these animals are nocturnal, especially carnivores, while others are deep sea animals. Similar adaptations occur in some species of spiders. Haplorhine primates, including humans, are diurnal and lack a<unk> .
Tapetum lucidum
Corona radiata 
Stratum basale
Glia limitans
Stratum lucidum
Neuromatrix
Stratum spinosum
Habenular nuclei