Inside a "Touch Me Not sponge

Some time ago I posted an image with these inside but did not have the magnification to get closer, I said I would post them again when I did, so here they are, did we find out what they were?

Another bigger and another wider.

Some time ago I posted an image with these inside but did not have the magnification to get closer, I said I would post them again when I did, so here they are, did we find out what they were?

You are my HERO, Patrick! And those are just gorgeous photos!

Polychaete worms, family Syllidae, genus Haplosyllis, possibly undescribed species. Not that long ago it would have been called Haplosyllis spongicola, one of the so-called cosmopolitan species. These species were thought to show up pretty much everywhere around the world in the right habitat. Spongicola means sponge inhabitant, so every Haplosyllis living in a sponge was put into this species. Researchers taking a closer look at these guys from different areas have found big physical differences (well, as big as you can get in a worm that's probably only half an inch long) and are busy describing these new species.

Anyway, all of the species do live in sponges. See the two white areas behind the head? The first one - looks like 2 white lines & the rim shows up as a circle in the little guy standing up - is the pharynx. This portion of the digestive tract attaches to sponge cells & forms a vacuum. The second white area - the cylinder - is the proventricle which is made of many rings of muscle cells. It functions as a pump, expanding & contracting, which gives the worm the suction it needs to feed on contents of the sponge cells. The sponges are fast growing to compensate for all the cells the worms eat. In return, the worms defend their host sponges. If a predator comes around all the worms will rush over & start biting it so the sponge actually does benefit from the association.

Many thanks for posting them--