Urchin Exoskeletons

Urchin Exoskeletons

“Pentact Test”, in 10%+ page 97, displayed features of an echinoderm’s skeleton (called a “test” in biology). The spines, individually mobile, may sweep to and fro or stick straight out. They are not an intrinsic part of the skeleton and may break off. Spines are not poisonous–that is instead a quality of the globiferous pedicellariae highlighted in the last post.

The somewhat humerous youtube video from whence this icon comes has been added to the youtube section, showcasing the versatility of these spines–not only as a defense, but as appendages.

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