 The mouth of the holotype of Corythosaurus is narrow . The praemaxillae each form two long folds . The folds enclose air passages extending the narial passages to the front of the snout . There they end in narrow openings , sometimes called " pseudonares " , 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 , in Kritosaurus , the bill is short , and the pseudonares extend far forward . At the end of the Corythosaurus bill , the two pseudonares unite into one . 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 , another difference from those genera . The praemaxilla actually does touch the lacrimal and extends to the rear until well behind the eye socket . 
 The mouth of the holotype of Corythosaurus <a href='drop_aux' title='1'><mark>is</mark></a>narrow . The praemaxillae each form two long folds . The <a href='uninflect' title='2'><mark>folds</mark></a> enclose air passages extending the narial passages to the front of the snout . There they end in narrow openings , sometimes called " pseudonares " , false bony nostrils . These <a href='uninflect' title='3'><mark>were</mark></a> 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 <a href='null_genetive' title='4'><mark>'</mark></a>opening is elongate : by comparison , in Kritosaurus , the bill is short , and the pseudonares extend far forward . At the end of the Corythosaurus bill , the two pseudonares unite into one . Because of his incorrect identification , Brown assumed that the holotype <a href='null_genetive' title='5'><mark>'s</mark></a>inferior process of the premaxillary was shorter than in Kritosaurus and Saurolophus , and that the process <a href='uninflect' title='6'><mark>does</mark></a> not unite with the lacrimal , <a href='None' title='7'><mark>another</mark></a><a href='negative_concord' title='8'><mark>difference</mark></a> from those genera . The praemaxilla actually <a href='uninflect' title='9'><mark>does</mark></a> touch the lacrimal and <a href='uninflect' title='10'><mark>extends</mark></a> to the rear until well behind the eye socket . 
Da mouth of tdaholotype of Corythosaurus narrow . The praemaxillae each form two long folds . Thdaold enclose air passages extending the narial passages to the front of the snout . thea they end in narrow openings , sometimes called " pseudonares " , false bony nostrils . dem was mistaken by Brown fir thedaal nares or nostrils . These r actually situated inside the crest , above the eye sockets . As in Saurolophus , the daanded portion of the pdaaxillary in front of the psdaonaris  opening is elongate : by comparison , in Kritosaurus , the bildas short , and the pseudonares extend far forward . At the end dathe Corythosaurus bill , the two pdadonares unite into one . b/c of his incorrect identification , Brown assumed dat the holotype  inferior process of the premaxillary was shorter than in Kritosaurus and Saurolophus , and tdatthe procesdao not unite with the lacrimal , no difference from those genera . The praemaxilla actually do touch the lacrimal and extend to the rear until well behind the eye socda .