In the chondrocranium of mice with induced cleft palates, the ethmoid region is not affected by this malformation. The paramedian cartilagenous structures of the orbito-temporal region of 17-day-old and new-born mice, however, show a distinct reduction in dorso-ventral height. These deformities prove that the cleft palate malformation is not topographically restricted to the palate. It is assumed that both the cleft palate and accompanying alterations are due to to defective induction in the prechordal area of the embryonic head.