For example, the skull of a placoderm had an internal braincase made of endoskeletal bone.
例如,盾皮动物的头骨有一个由内骨骼骨制成的内部脑壳。
英语百科
Endoskeleton
An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue.