Post #14 - What is it?

It's been a busy day in the lab, but the afternoon ended with a quick snorkeling trip.  Saw some things I thought you'd like to see, though they are presented here through a serious of questions.....

(It was a late afternoon snorkel, with threatening clouds.  If fact, it was raining by the time we were getting out, and pouring later.  Because of the time of day and weather, the colors in these pictures are rather muted.)


First question: This is a close-up of what?

The top side of a cushion star, which like the COT eats corals.  This one is about 6 inches across:

Second question: What kind of animal produces all this mucous coming out of a hole (at least 4 of which you see here) in the coral?

It's hard to believe it's a snail, but not at all like this cowry which crawls about freely:

The mucous is a sticky trap for organic rich particles that are reeled in and eaten (along with the mucous) by vermetid snails.  The shells of these animals look more like the calcareous tube of some fan worms, and are usually buried down in the coral skeleton but not here:

The round dark "trap door" is the operculum, just like that of most free-crawling snails that block the opening to the shell should a predator arrive.  In this full-sized animal, the operculum is just less than an inch across.

Third question: What did Emily take a picture of here?  An eel?  A snake?  A worm?

Nope - it's a sea cucumber, at least the back 12 inches of it.  If you touch it it feels "sticky" because tiny barbed ossicles (little bones) protrude from the skin.

Lastly, see if you can find Waldo, the 3 inch baby flounder: