Concept
Version 11
Created by Boundless
ChimĂș
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"Spondylus."
http://en.wikipedia.org/wiki/Spondylus%23mediaviewer/File:Spondylus.jpg
Wikipedia
CC BY-SA 3.0.