What are the similarities and differences of the neural crest cells of the Craniates and imaginal disks of the Ecdysozoa?  In a broad sense, both involve groups of cells that are “programmed” during development with information about pattern and position, and these cell groups later organize (and sometimes move around to do so) the sequence of developmental steps key to the emergence of the Bauplan.  While imaginal disks and neural crest cells cannot be, in any simple sense, homologous, are there underlying homologies?  If so, then such homologies could reveal key aspects of Eumatazoan architecture, in the same that Hox gene loci do, because such homologies would predate the Protostome/Deuterostome split ca. 600mya.