Worm-like things

I found these during my holiday. They were in and around the larger tubular structure, which is the excretion of what i think is a Arenicola type species.

They don't look segmented, so I suppose they're not polychaetes. I had a look through my old books (Hayward and Ryland, handbook marine fauna), but i just don't know where to look. They are almost smooth like nematods, could it be a large species?

Any toughts?

link to larger size

More likely the filaments belong to a cirratulid worm which is buried just under the castings.

ah, Gerard, your post would have been the perfect opportunity to use the word vermiform!

Scott

LOL !!

I had to look that one up (amazed to see there's a vermiform records). Anyway, i looked the answer from Leslie up. Sounds clear enough, and also explains why there were so many.

How are worms feeding? Assuming that they don't feed from the sediment itself (since the filaments are above the surface). To transport the food to the mouth, there would be a centrum somewhere. Or is it transported within the tentacles /filaments?

Gerard

Cirratulids have two types of appendages. Up by the head are the feeding appendages called palps - either 1 pair or several depending on the genus. These are grooved & lined with cilia to pick up particles of detritius or sand grains & carry them down to the mouth. Along the body are multiple pairs of branchiae - gills - that stick up out of the sediment & absorb oxygen from the water. They're very efficient which is why cirratulids are common in polluted or low-oxygen areas where other organisms have trouble surviving.

There's another image of cirratulid branchiae sticking up here http://marine1.bio.sci.toho-u.ac.jp/tokyob...idellidae1.html and if you're really interested here's an account of how one species feeds

http://www.scielo.br/scielo.php?script=sci...842004000200014