part of part_of part of part_of contributes to morphology of anterior chamber of eyeball aqueous humor of eyeball (...) we reach the inescapable conclusion that the last common ancestor of jawless and jawed vertebrates already possessed an eye that was comparable to that of extant lampreys and gnathostomes. Accordingly, a vertebrate camera-like eye must have been present by the time that lampreys and gnathostomes diverged, around 500 Mya (reference 1); Although the eye varies greatly in adaptative details among vertebrates, its basic structure is the same in all. The human eye is representative of the design typical for a tetrapod. (...) A watery aqueous humor fills the spaces in the eye in front of the lens (...) (reference 2).[well established][VHOG] A thick watery refractive medium that fills the space between the lens and the cornea[WP]. EHDAA2:0000139 EHDAA:10196 EMAPA:18232 ENVO:02000024 FMA says A+P chambers, and MA states A chamber. ZFA states A chamber and tha it is produced primarily by dorsal ciliary epithelial cells.To be investigated across taxa. FMA:58819 GAID:890 MA:0001236 MESH:D001082 NCIT:C13190 OpenCyc:Mx4rvdGd-5wpEbGdrcN5Y29ycA The fluid produced by the ciliary process in the eye and occupying the anterior and posterior chambers. It provides nourishment for the lens and cornea and maintains the ocular pressure, and hence the optical integrity of the eyeball. [TFD][VHOG] UBERON:0001796 UMLS:C0003662 VHOG:0000548 ZFA:0005564 aqueous humor aqueous humour humor aquosus uberon ocular refractive media bodily fluid