Fig. 3. Morphological and histological analysis of Chrd^-/- newborn mice. (A,A') External appearance of wild-type (A) and homozygous mutant (A') mice. The mutants appear cyanotic; their external ear is reduced and set closer to the eye than in wild type. (B,B') Sagittal sections of wild-type (B) and mutant (B') mice. In the mutant, the secondary palate (p) and thymus (t) are absent and the laryngeal cartilages (l) are severely reduced in size. The overall morphology and size of the central nervous system was not affected. (C,C') Coronal sections of wild-type (C) and mutant (C') mice at the level of the neck. Note the absence of the inner ear (ie) and oesophagus (oe), and the reduction in size of the trachea (tr) and thyroid (th). pi, pituitary gland.