chondrocrania

the cartilaginous skeleton enclosing the brain, olfactory region, eye and inner ear. Part of skull first formed in the embryo. Forms the whole skull in Cyclostomata, Elasmobranchii and Holocephali. Covered by dermal bones in Teleostomi and replaced by the osteocranium with only remnants between bones allowing for growth. Sometimes called the neurocranium or endocranium