The skull also featured a pair of "brow" or supraorbital horns approximately long, with one above each eye. The jugal bones pointed to below at the rear sides of the skull and were capped by separate epijugals. With "Triceratops" these were not particularly large and sometimes touched the quadratojugals. The bones of the skull roof were fused. By a folding of the frontal bones, a "double" skull roof was created. In "Triceratops", some specimens show a fontanelle, an opening in the upper roof layer. The cavity between the layers invaded the bone cores of the brow horns.