A friendly face

Meet Mr. Fangs!

Polychaetes always look worried.

This was a polychaete worm that grew from an almost microscopic red hair in the sand of my tank, to a fat, active, foot-long wriggler. He has been relocated to the beach; he's at close to his full size and mating season is coming up soon. Happy hunting, Mr. Fangs!

Actually, those two front projections aren't fangs. They're antennae; the other six projections around his head are tentacles. The front paddles are palps, for handling things. He seems to have four eyes, although I would need a closer photo to be sure.

I found a page that describes these worms beautifully, with a long section on the structures of the head. It includes this diagram, which I found helpful.

Image from Reefkeeping.

Ronald Shimek explains:

This diagram represents the head of a generalized polychaete as viewed from above. I know of no real animal with all of these structures in this pattern. However, there are worms having some of all of the structures illustrated here.