Lambeosaurinae
Lambeosaurinae is a sub-family of dinosaurs.  They are hadrosaurs, or duck-billed dinosaurs.  Dinosaurs in Lambeosaurinae had crests on their heads.  The crests had hollow tubes in them.  Scientists are not sure what the crest was for.  They might have been tubes that let the dinosaur breathe while it was underwater, like a snorkel.  They might have helped the dinosaur make sounds.