 <unk> of most of the bones of <unk> are also seen in other early <unk> , aside from a few bones in the skull , such as <unk> , <unk> , and <unk> , that have developed in some <unk> taxa . Most <unk> have <unk> horns in the backs of their skulls , rounded projections of bone separated from the rest of the skull by <unk> called <unk> <unk> ; in some <unk> , such as <unk> , they are pointed and very prominent . Among the most distinguishing features of <unk> are the <unk> <unk> , two large holes in the back of the palate . Another pair of holes , <unk> , are present in front of these <unk> , and connect the nasal passage with the mouth . <unk> often have teeth on their <unk> , as well as in their jaws . Some of these teeth are so large , they are referred to as <unk> . In some <unk> , such as <unk> , <unk> in the lower jaw <unk> the palate and emerge through openings in the top of the skull . 
