 The crests of Corythosaurus resemble that of a cassowary , or a Corinthian helmet . They are formed by a combination of the praemaxillae , nasals , prefrontals and frontals , as in Saurolophus , but instead of projecting backwards as a spine , they rise up to make the highest point above the orbit . The two halves of the crest are separated by a median <unk> . In front of the orbit , the crest is made of thick bone . 
