Re: live birth

["Jeff J. Liston" <JLISTON@museum.gla.ac.uk>]

Sorry, Bill, I was afraid I might not be making myself very clear.  
The 'Critical Size Threshold' was a nice pretentious jargon term, to 
describe the point at which a youngster would become visually 
'obvious' to a parent, and avoid running the risk of being flattened.

It just strikes me that if they developed to that  [C.S.T. (:-)] size (again, 
this 
is assuming that a) parental care as evidenced by trackways began 
near hatching, and b) that they used sight as their main indication of 
the specific whereabouts of their offspring, so as not to crush 
them), it would be easier (in biological terms) for them to do it 
either within the animal, so necessitating viviparity, or in a large 
egg -[ which there are structural problems with] - rather than 
growing from any of the eggs we've so far seen.

Thanks for the Camarasaur reference as well (I have to confess, we 
got a copy of 'Dinosaur Eggs and Babies' the day it came out......but 
I haven't had a chance to do more than flick through it---not good).

But thanks, everyone, for the feedback.  It really helps the research 
we're doing just now on our own clutch, and is inputting a lot of 
fresh ideas into some problems I've had with 'large bronto adult/ 
teeny bronto wain[kid]' for some time.

J.J.Liston
Hunterian Museum
University of Glasgow
SCOTLAND