Any idea what this is?

[MacHeath]

Can anyone tell me what this is? Is it a worm? A crab?
About 10mm long, living on top of the sand. The animal seemed to be able to come out of either end, but was too small to really see much with the naked eye.

 

[the_cat_keeper]

Reminds me of a miniature bamboo clam (some people called it bamboo worm) that you can find in seafood restaurants in Kuching, Sarawak, East Malaysia. Those bamboo clams are a few cm long though. I suspect the one you have shot is some kind of a cousin to it.

 

[maractwin]

I'd say it's a polychaete worm of some sort. The bottom of the tube in the picture looks broken; it probably used to be attached or buried.

-Mark

 

[LeslieH]

Polychaete is a good guess but I'm pretty sure it's a tube-dwelling amphipod crustacean. I'e seen a lot of similar ones from California and the Caribbean. They build the tubes out of mucus and silt. The front legs are used outside of the tube to move the tube around while the rear legs inside hold onto the tube. What's showing are the two pairs of antennae. When a predator comes by the animal completely retracts into the tube to hide.