Fig. 23. Region of angle of a fetus at 170 mm (approximately 5 months), showing thick iris root with a branch from the major arterial circle (arrowheads) passing into the primitive iris stroma (Ir), in which the vessels are layered at two levels (curved arrows). The pigment epithelium is indented by thin-walled vessels (astericks). AC, anterior chamber; ci, nonpigmented ciliary epithelium (oblique to the plane of section); C, cornea; cs, canal of Schlemm; Tr, trabecular metshwork.