Revision as of 19:08, 2 March 2011 by Bio man(Talk | contribs)(Created page with "An internal skeleton covered by soft tissue; composed of calcareous plates overlaid by a thin skin in echinoderms and composed of a bony skeleton overlaid by muscles in invertebr...")
An internal skeleton covered by soft tissue; composed of calcareous plates overlaid by a thin skin in echinoderms and composed of a bony skeleton overlaid by muscles in invertebrates.
