On a night dive last week in Bonaire I saw 2 things I have never seen before and I would appreciate some help with identification.

Here is the 1st--it looked soft and flexible, for lack of better descriptive words


The 2nd thing is this little ball on top of this sea urchin---what is that?



Thanks for your help!

The first looks like Cup Corallimorph. Not sure of the function of the ball on the urcheon other than it's part of the urcheon.

Can't tell what you are referring to from the urchin picture. The orange ball (lower left) is not part of the urchin - possibly a sponge. In any case, something the urchin ran into, not part of it. I can barely imagine a tiny ball at the center of the urchin with the spines radiating out from it. If that's what you are referring to, it's the body of the urchin. Contains the mouth and functional parts.

Bas, I think you are right on the corallimorph--thanks!!

As for the urchin--I am not talking about the orange thing---but rather the small whitish ball on top of the urchin---there are no spines coming from it. I am sure it is part of the urchin---but what part? I have just never seen this before.

reproductive parts? when they spawn, 'smoke' comes from that ball. The mouth is underneath the urcheon.

sorry about that Jen I got called out.. here are the photos a bit larger and lighter..

http://en.wikipedia.org/wiki/Sea_urchin
1/2 way down the page under ecology title,there's a picture on the right.....the "ball" is, the anus.

Yes, Brenda is correct. Urchins are up-side-down, with the teeth and mouth underneath and the ball of waste, or reproductive material protrudes from the "top".

Another interesting thing about the night-time pic of the sea urchin is the fact that at night, the spines turn tan and brown, but in the daylight are so dark as to appear black. Apparently, sea urchins have to be added to the list of color-change marine creatures. Any ideas as to why the color change is advantageous to them?

Long Spine Urchins change spine color as they mature, Mid-way to maturity is the tan and brown phase, with the eventual dominant color being black. But, they are not "color changing" marine critters.