Saturday, October 03, 2009

Worm in a coat of many colours

The tide was high Friday afternoon on the White Rock beach, and still coming in. In the few feet between the waves and the mounds of rotting seaweeds, Laurie started idly flipping rocks, looking for crabs. At this level, there's usually not much else.

Under the rocks just lying on the surface, there was nothing. Rocks embedded just a bit yielded tiny shore crabs and squirming, hopping mounds of blue-green amphipods.


The slowpokes; the rest are long gone.

I turned over a rock that was buried just a bit deeper, and something pink slithered out of sight down a hole. I dug it out and dumped it on a rock; it was a worm, at first glance looking like an earthworm, but in the sunlight, it shimmered with blue, green and yellow highlights. Frilly legs on the side identified it as a polychaete.

Worm #1

Under another rock, we found a second worm, a smaller one. Turning its rock around for a better view, Laurie inadvertently broke a couple of rings off the tail. (This is important; you'll see why in a bit.)

The two polychaetes at home, in a soup bowl. The long one is just under 4 inches.

I photographed these as well as I could, given that they never, ever, stop moving. Then I dumped them into the aquarium with the rest of my critters. They disappeared into the sand at the bottom.

Later, sorting the photos, and attempting an identification, I was stymied by the lack of detail in the faces; these were Nereids, it seemed, but I couldn't be sure.

There was only one solution: I emptied all the water out of the aquarium, carefully removed rocks and shells and seaweeds, making sure I didn't squish any of the anemones. Crabs and hermits scuttled out of the way; the barnacles and snails shut down. They would be fine.

I ran my fingers gently through the sand, and exposed a worm. Hooray! I fished it out and dumped it in clean water. But wasn't it bigger than I remembered? Seemed so. Maybe my memory is going.

I found the second and added it to the bowl. But -- what was this? Its tail isn't broken!

And no, my memory is fine. This second one is Worm #1, the 4-inch one. Worm #2 is still in the sand. The other one has been living in my sand bed -- how long? And how did it get there?

This worm is over 7 inches long, stretched out. It's as squirmy and wriggly as the other two, but I was glad of this; with each twist, its colours changed; it's a multi-legged rainbow!

These photos are blurry, and don't do justice to the iridescence of the original, but will give an idea of the variety of colours:

Tail end of worm #2, on the rock in the sunshine. The red line is the main blood vessel, running from head to tail.

Worm #3, in a plastic container. Every movement sent shivers of blue down the spine.

Under more gentle light, the colours are muted, but the pink reflects in the water around.

And I got my head shots, more or less.

Yes, those are eyes, two large and two small, just above. The little "V" in front are antennae; on either side, shaped rather like a Tegenaria's fangs, are the jaws or palps. The four spikes on either side are cirri.

Side view of the head.

And the tail, with a cute little button at the end.

Looking at the head, I think I can identify it as a Nereis, probably vexillosa, known variously as the sea-nymph, mussel worm, sand-worm, piling worm, etc. It grows to about 15 cm, although some may reach up to 30. (One foot.) Kozloff (Seashore Life of Puget Sound) says it eats algae, tearing it with those heavy jaws; some websites tell me it's a "active predator" that feeds on soft-bodied animals. If it's been living in my tank for a while (and it must have; the only way it could have arrived would be as a tiny red worm in a pill-bottle of sand), then it hasn't been feasting on the other animals; they are all multiplying happily in there.

I found a page of a lab manual on dealing with Nereids; I read,
They are difficult to handle before they are completely relaxed.
No kidding!


  1. This comment has been removed by a blog administrator.

  2. Anonymous1:56 pm

    Hi Weeta,
    Yes, probably Nereis, but can't say for sure which species. You need to examine the setae along the body for that.
    The palps have nothing to do with feeding. They are strictly sensory in nature. You haven't seen the fangs and denticles yet -- they are on the proboscis that unfolds from the mouth to capture it's food.
    Judy Fournier


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