David Fenwick Snr Hi I'm Dave, I've an interest in flatworms found intertidally in the UK. Have attached an image of what I think might be a cocoon forming flatworm and one I've yet to identify. A number of these cocoons / egg sacs were found in a corner of a fish box that was washed up at Porth Kidney Sands, near Hayle, Cornwall, England, United Kingdom. The fish box also contained Lepas anatifera, the Common Stalked or Gooseneck Barnacle; Prickly Saddle Oyster (Heteranomia squamula); and one or two species of hydroid. The box has therefore probably been washed across the Atlantic from the USA, Canada or further. I'd b interested in any suggestions at all.
David Fenwick Snr Other images can be found on the following webpage http://www.aphotomarine.com/help_identify_marine_sea_ball_cocoon.html