[Scand.] The bony case which encloses the brain, and with the bones of the face and mouth gives shape to the head. It is rounded on the top somewhat like the large end of an egg, and in front and on the sides it has openings for the eyes, the nose, and the ears. The skull is made up of compact plates, joined by irregular saw-like lines or projections called sutures. The upper jaw and the bones of the nose and cheeks belong to the skull, and are immovable. The use of having the skull in several parts is 10 allow the brain to grow, and to prevent a jar from affecting the whole skull. In many fishes the skull is almost wholly cartilaginous, with a layer of spongy bones.