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