Editing Endoskeleton (section)

=== Echinoderms ===
Echinoderms have a [[mesoderm]]al skeleton in the [[dermis]], composed of [[calcite]]-based plates known as [[ossicle (echinoderm)|ossicle]]s, which form a porous structure known as [[stereom]].<ref>{{cite book |last1=Behrens |first1=Peter |last2=Bäuerlein |first2=Edmund |title=Handbook of Biomineralization: Biomimetic and bioinspired chemistry' |year=2007 |publisher=Wiley-VCH |isbn=978-3-527-31805-6 |page=393 }}</ref><ref>{{cite book | last1=Brusca | first1=Richard C. | last2=Moore | first2=Wendy | last3=Shuster | first3=Stephen M. | title=Invertebrates |edition=3rd | publisher = Sinauer Associates | publication-place=Sunderland, Massachusetts | date=2016 | isbn=978-1-60535-375-3 | oclc=928750550 |pp=979–980}}</ref> In [[sea urchin]]s, the ossicles are fused together into a [[test (biology)|test]], while in the arms of [[sea star]]s, [[brittle star]]s and [[crinoid]]s (sea lilies) they articulate to form flexible joints. The ossicles may bear external projections in the form of [[spine (zoology)|spine]]s, granules or warts that are supported by a tough [[epidermis (zoology)|epidermis]]. Echinoderm skeletal elements are sometimes deployed in specialized ways such as the [[chewing]] organ in sea urchins called "[[Aristotle's lantern]]", the supportive stalks of crinoids, and the structural "lime ring" of [[sea cucumber]]s.<ref>{{cite book |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard S. |last3=Barnes |first3=Robert D. |title=Invertebrate Zoology |edition=7th |year=2004 |publisher=Cengage Learning |isbn=81-315-0104-3|p=873 }}</ref>