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Re: CNN on Lungs and Feathers

At 09:55 PM 1/5/98 -0800, Terry D. Jones wrote:
>So by this reasoning turtles, crocs, and lizards--animals with 
>pneumatized vertebrae--also had air sacs?

Do they have true pneumatized vertebrae, or merely excavated vertebrae?
There is a difference.  (Look at the cross-section of an _Allosaurus_
vertebra in Farlow's book to see what I mean).  That sort of structure only
forms where epithelial tissue invades the bone.

May the peace of God be with you.         sarima@ix.netcom.com