Thanks Andrew - as usual you are a font of knowledge!!!  My specimen is
about 70mm, and has a VERY open umbilicus of several mm - 5 or 6, with
no indication that it is in the process of closing.   Perhaps this in
itself is unusual - i recall another similar-sized specimen that had a
completely closed umbilicus, just like in a normal adult.

No, the pretty pipers peep not,
Ross M.