part of part of has part has part adjacent to adjacent to eye photoreceptor cell layer of retina photoreceptor layer of retina http://upload.wikimedia.org/wikipedia/commons/5/55/Gray881.png MA:0001308 NCIT:C32954 (...) an essentially similar sequence of events occurs during the embryonic development of the vertebrate eye. The eye initially develops as a single median evagination of the diencephalon that soon bifurcates to form the paired optic vesicles. As each optic vesicle grows towards the body surface, its proximal part narrows as the optic stalk, and its distal part invaginates to form a two-layered optic cup. (...) The outer layer of the optic cup becomes the pigment layer of the retina, whereas the inner layer differentiates into the photoreceptive cells and neuronal layers of the retina.[well established][VHOG] ZFA:0000143 Wikipedia:Layer_of_rods_and_cones retina photoreceptor layer UBERON:0001787 stratum segmentorum externorum et internorum (retina) The layer within the retina where the photoreceptor cell receptor segments reside. XAO:0003215 TAO:0000143 stratum segmentorum externorum et internorum retinae EMAPA:35686 retinal photoreceptor layers VHOG:0001165 layer of rods and cones retinal photoreceptor layer FMA:58680 UMLS:C0229206 we follow MA and ZFA in subdividing this into inner and outer segments outer limiting layer of retina retinal neural layer