Figure 3D of Hecksher-Sorensen J; Watson RP; Lettice LA; Serup P; Eley L; De Angelis C; Ahlgren U; Hill RE, 2004 [PMID:15329346] . Copyright: This image is from Hecksher-Sorensen J, Development 2004 Oct;131(19):4665-75 and is displayed with the permission of The Company of Biologists Limited who owns the Copyright.