I have to ask, what is a green common urchin? I thought I have had at least one of all but the long spined (don't make me look up the name please) but I am not familiar with a "green common". If you don't know its official name, can you describe it a little? Does it pickup shells and anything loose? Does it have stripes of "velcro"? Is it short or long spined? Are the spines very hard and pointy or short and sticky? Do you know which ocean it comes from? Sorry for all the questions but I enjoy my urchins and thought I knew most of the most "common".