chon·dro·cra·ni·um 
(kŏn′drō-krānē-əm)
(kŏn′drō-krānē-əm)n. pl. chon·dro·cra·ni·ums or chon·dro·cra·ni·a (-nē-ə)
1. The cartilaginous cranium of an embryo before ossification.
2. A portion of the embryonic cranium forming the bones of the base of the skull and eventually undergoing ossification.