Fig. 1. Xenopus retinal axons express EphA receptors. Explants from 2 day Xenopus retinae were grown on matrigel for 48 hours. (A) Incubation with ephrin-A5-AP, which binds all EphA receptors, results in a dark labelling of retinal axons. (B) Incubation with AP alone leads to no staining. Scale bar:100 µm.