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It was written that:

==>Turtles are constrained by ovipary. It may work like this: (1)
embryo turtles derive calcium from the eggshell, (2) turtles cannot
dispense with eggshells, etc<==

I see a break in the logic here; let me add a rider,
eggshells derive their calcium from the mother.

Therefore can the embryo not derive calcium from the mother instead of
the (secondary source) of the eggshell?!?

It was also written that:

==>The same _might_ go for marine crocs like metriorhynchids (my 
only reference for this - AFAIK he is only author who has really 
commented on it - is Tarsitano 1983).<==

Danny Grange (then a research student, at Bristol University), at the
SVPCA (1996, University College London) presented a paper entitled
'Locomotion in metriorhynchid crocodilians' (no idea if this was ever
published) in which he concluded met. crocs. could not walk on land
(based on limb girdle morphology) I never got to broach the question
of implications that this would be the only recorded crocodilian to be
a live bearer. I must admit I was not 100% convinced by the arguments
based on functional morphology/comparative anatomy, although that was
a while ago.

'nuff said


Leslie Noe

Centre of Environmental, Earth and Applied Science Research,
School of Environmental and Applied Sciences,
University of Derby,
Kedleston Road,
Derby, DE22 1GB,

e-mail: L.F.Noe@derby.ac.uk