What are these?

[inestrinh]

These appeared in my tank about three weeks ago, can anyone tell me what they are? They have been growing out of a piece of live rock I have had in my tank for about three months now. This isn't the greatest pic but it is the best I can do.

http://photos.yahoo.com/inestrin

thanks

 

[inestrinh]

oops i forgot to mention that in the pic they are the small white sac looking things in the middle of the photo.

 

[pr0teus]

linky no worky for me