
I think
en.wikipedia.org/wiki/Horseshoe_crab
( , Wed 9 Jan 2008, 12:38, Reply)

(Thank you to Pops for this link) www.glaucus.org.uk/spider.htm
I think we have a winner. The girls will be very pleased as they have a (still spiny) spider crab shell which is from a specimen we ate, and will be able to compare.
( , Wed 9 Jan 2008, 12:42, Reply)

It's the flap remains,
so it's the underside, which means that the actual crab must have been mahussive.
( , Wed 9 Jan 2008, 12:47, Reply)

the exco-skeleton is alive like our skin and changes colour to suit enviroment, now its dead its just whiteish...
the meat was on the inside..
( , Wed 9 Jan 2008, 13:07, Reply)

www.tnaqua.org/Newsroom/HighRes/SpiderCrab_popup.jpg
The flap at the bottom of that image.
( , Wed 9 Jan 2008, 19:24, Reply)