Stranded Sea Urchins

The winter storms left many things stranded on the beaches including sea urchins.  I found a lot of these on Pagham beach and I think they are Psammechinus miliaris, the Green Sea Urchin. Actually, there are several green species, but these are the ones most likely to crop up on the English Channel coast.  Mostly we find the Edible Sea urchin (would you like to eat one?) Echinus esculentus, but I have not seen any recently.