snails/worms? living on my astrea snails?

[Melina]

I don't have a picture, but living in the shells of a few of my astrea snails, are these long, thin black things. They have their own little shells (same color and texture as the snail's shell, but distinctly separate "homes", on top of, and fused to, the main shell), .. like, hitchhikers I guess... on the backs of the snails, in their own little "houses". They extend a long (1"?) "neck" and are jet black. They have two small antennae, similar to a snail, (on each side of the "neck", protruding from their shells) but their method of feeding is much different. They extend their long "necks", and "graze" (peck?) at the rocks. At the end of their necks, appear to be two tiny feelers? which open and close, or scrape? like a mouth. It extends, feeds, retracts back into it's shell, extends again. Can anyone tell me what these things are?

[fmelindy]

yeah, I had the exact same thing in rather large numbers living on the shells of my turbo snails. Didn't seem to harm them at all and I observed them picking at the rocks as you did. They also seemed to move over the shell and even kept the shells clean. Too bad I didn't get pics of them. I just assumed they were like some kind of "hitch-hiker snails" but I'm curious as well..

[bassman]

I have recently discovered the same thing happening with my turbo snails, one snail has 6-7 critters living on it.

Did you ever learn anymore about these hitchhikers? Do you still have them or did they eventually separate?

[Melina]

No, I have not been able to learn more about these critters. I still have them. They are still on the shells... have not separated.

[bassman]

Strange, I can't find any information either. They look like babies to me, the shells are forming identical to the host snail. I'm betting they detach one day.