[Taxacom] Reptilian double-eyelid

[Kenneth Kinman]

Dear All,
      I was looking at a cladogram online that showed living reptiles
with a synapomorphy of "double eyelids", as opposed to birds (which
apparently lack them.  Since birds are reptile descendants, this
indicates that they must have lost this synapomorphy.           
      Unfortunately, I was unable to find anything else on this supposed
"synapomorphy" that was reversed in birds.  Is there a technical term
for "double-eyelids" that might turn up more information?  Do turtles
have such "double-eyelids"?
        -----Thanks,
                    Ken Kinman