Editing Corythosaurus (section)

===Skull===
[[File:Life reconstruction of Corythosaurus casuarius.png|thumb|right|[[Life restoration]] of ''C. casuarius'']] 
Over twenty skulls have been found from this dinosaur. As with other lambeosaurines, the animal bore a tall, elaborate, bony crest atop its skull that contained the elongate narial passages.<ref name="ageofdinosaurscorythosaurus"/> The narial passages extended into the crest, first into separate pockets in the sides, then into a single central chamber, and onward into the respiratory system.<ref name="benson2012"/><ref name="ageofdinosaurscorythosaurus"/> The skull of the type specimen has no dermal impressions on it. During preservation, it was compressed laterally and the width is now about two-thirds of what it would have been in real life. According to Brown, the compression also caused the nasals to shift where they pressed down on the premaxillaries. Because they were pressed on the premaxillaries, the nasals would have closed the nares.<ref name="brown1914p561"/> Apart from the compression, the skull appears to be normal.<ref name="brown1914p561"/> Contrary to what Brown assumed, the areas concerned were fully part of the praemaxillae.

As aforementioned, the crests of ''Corythosaurus'' resemble that of a [[cassowary]] or a [[Corinthian helmet]].<ref name="benson2012"/> 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 suture. In front of the orbit, the crest is made of thick bone.<ref name="brown1914p561"/>
[[File:Corythosaurus Hendrickx2.jpg|left|thumb|Skull of the type specimen]]
The nasals make up most of the crest. Brown assumed that they extended from the beaks' tip to the highest spot along the crest and that, unlike those in other genera, the nasals meet in the center and are not separated in front by an ascending premaxillary process. However, Brown mistook the praemaxillae for the nasals. The snout is actually largely formed by them and they do separate the nasals. Brown also thought that, on the top and back of the crest, the whole external face is covered by the frontals. Again he made a mistake, as what he assumed to be the frontals are in fact the nasals. The nasals end at the back of the squamosals in a hooked, short process.<ref name="brown1914p561"/> The prefrontals also make up part of the crest. However, Brown mistook the lower upper branch of the praemaxilla for the prefrontal. The actual prefrontal, which is triangular in shape, is located at the side of the crest base. It was seen by Brown as a part of the frontal. The real frontals, which are largely internal to the crest base structure, are not visible from the side.<ref>Weishampel, D.B., Dodson, P., Osmólska, H., & Hilton, Richard P., 2004, ''The Dinosauria''. University of California Press. p. 450</ref>

The mouth of the holotype of ''Corythosaurus'' is narrow. The praemaxillae each form two long folds that enclose air passages extending the narial passages to the front of the snout. There, they end in narrow openings, sometimes called "pseudonares", which are false bony nostrils. These were mistaken by Brown for the real nares or nostrils. These are actually situated inside the crest, above the eye sockets. As in ''Saurolophus'', the expanded portion of the premaxillary in front of the pseudonaris' opening is elongate. By comparison, the bill of ''Kritosaurus'' is short and the pseudonares extend far forward. At the end of the ''Corythosaurus'' bill, the two pseudonares unite into one.<ref name="brown1914p561"/> Because of his incorrect identification, Brown assumed that the holotype's inferior process of the premaxillary was shorter than in ''Kritosaurus'' and ''Saurolophus'' and that the process does not unite with the [[lacrimal gland|lacrimal]], which is another difference from those genera.<ref name="brown1914p561"/> The praemaxilla actually does touch the lacrimal and extends to the rear until well behind the eye socket.

The lower jaw of the holotype is {{convert|66.9|cm|in}} long and {{convert|10|cm|in}} deep. The total length of the crest from the beak to the uppermost tip of the type specimen is {{convert|83.7|cm|in}}, its total length is {{convert|81.2|cm|in}}, and its height is {{convert|70.8|cm|in}}.<ref name="brown1914p563"/>