Anatomy of Corals question

[edsreef]

Eric, someone used the description below to describe, in a nutshell, the anatomy of/and how corals work. I took issue with his choice of words, specifically the use of the word hydroids. I did some research and found it was possibly apllicable when speaking in terms of hydrocorals only. I don't want to try to pretend to be the expert so could you clear this up so I can quote you.

"A coral is a colony of individual hydroids attached and supplement each other through tissue connecting each hydroid. Overtime usually as the coral grows the hydroids at the bottom will get shaded and eventually stop extending. You still might have tissue over the skeleton but no polyps. Eventually over time as the table becomes more dense the tissue will start to recede. Leaving bare skeleton and giving a chance for other inverterbrates, mollusks etc to attach. This will form into "rock" overtime!"