BCL11B immunostaining in sections of embryonic faces (two upper rows represent sections from two different planes) and calvaria (lower row) at indicated stages. Osteogenic mesenchyme (om) is denoted by asterisk in the facial sections and outlined by blue line in the sections of calvaria. c, coronal suture; dm, dura mater; F, frontal bone; P, parietal bone. Scale bars: (two upper rows) 500 µm; (C), (F,I) 200 µm.