Summarizing presentation of the development and degeneration of the reciprocal retino-retinal projections in the chick embryo. A, Summary of the early stages (E6–E12) showing the central retino-fugal projections (blue) to the tecta, thalamus, and nucleus suprachiasmaticus (NS) and toward the area of ION (yellow). The reciprocal retino-retinal projections are marked in green andred and show from the beginning a hemiretinal topological projection from the nasal to the temporal half of the other site. B, At ∼E14, the retino-tectal topography is formed, the ipsilateral central retino-fugal projections degenerate, and the ION fibers have arrived at the retina. The retino-retinal axons are still present, whereas massive cell death occurs. C, At E16, microglial cells (pink) are labeled by phagocytosis, vital GCs have differentiated dendrites, and axons are still visible within the nasal part of the contralateral retina.D, At E18 and after hatching, the projections between the retinas disappear, and the only cells reminiscent of completed cell death are microglial cells. Persistent projections to and from the central targets display mature patterns.