Unravelling the Crest
Figure 12
- There are two types of crests: hollow and solid. The hollow ones are
connected with the external nares (nostrils) to form part of the respiratory apparatus. Some
have both hollow and solid crests, but others have one or the other.
- About half of the crest is actually flattened from side to side and only the
proximal portion is hollow.
- The external naris is very large and opens posteriorly into a fairly wide bony
canal.
- At about eye level, both left and right canals becomes an S-shaped bend.
Posterior to the bend, each tube widens into a large chamber.
- A single boney tube extends downward from the central chamber and connects to
the internal nares, which are located at the back of the throat.
- In another species, PARASAUROLOPHUS, the crest is large and projects backwards.
The two bony canals from each naris, which lack the S-bend, continue back to the end of the
crest, double back on themselves, and then pass forward again toward the throat.
- The lateral chambers are very long and extend back about half the length of
the crest. The central chamber is relatively small.
