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eubhttp://en.wikipedia.org/wiki/Tapetum_lucidum
A classification of anatomical variants of tapeta lucida[2] defines 4 types:
* Retinal tapetum, as seen in teleosts, crocodiles, marsupials and fruit bats. The tapetum lucidum is within the retina; in the other 3 types the tapetum is within the choroid behind the retina.
* Choroidal guanine tapetum, as seen in elasmobranchii (skates, rays, and sharks). The tapetum is a palisade of cells containing stacks of flat hexagonal crystals of guanine.[3]
* Choroidal tapetum cellulosum, as seen in carnivores, rodents and cetacea. The tapetum consists of layers of cells containing organized, highly refractive crystals. These crystals are diverse in shape and makeup.
* Choroidal tapetum fibrosum, as seen in cows, sheep, goats and horses. The tapetum is an array of extracellular fibers.
A classification of anatomical variants of tapeta lucida[2] defines 4 types:
* Retinal tapetum, as seen in teleosts, crocodiles, marsupials and fruit bats. The tapetum lucidum is within the retina; in the other 3 types the tapetum is within the choroid behind the retina.
* Choroidal guanine tapetum, as seen in elasmobranchii (skates, rays, and sharks). The tapetum is a palisade of cells containing stacks of flat hexagonal crystals of guanine.[3]
* Choroidal tapetum cellulosum, as seen in carnivores, rodents and cetacea. The tapetum consists of layers of cells containing organized, highly refractive crystals. These crystals are diverse in shape and makeup.
* Choroidal tapetum fibrosum, as seen in cows, sheep, goats and horses. The tapetum is an array of extracellular fibers.
