Cross section of development

This is cool! Where did you find it? I've only seen the black&white Haeckel image with embryo stages (And do you happen to know if it's in the public domain? I guess I can have a look around WikiMedia commons...)

I'm community manager for a developmental biology group blog (run by the journal Development, but authors are from everywhere) called the Node http://thenode.biologists.com and we *love* showcasing developmental biology images, so I'm bookmarking this for future reference. (You're also welcome to come post it over there if you want, but I don't want to take time away from your required course blogging!)