Last level of the game

Hi,
I'm on the last level. I have moved the,I think it was a shark, out of the way. Gone down into that area. I have opened the sarcophagus. The hints are telling me that there is a shell there, but I can't find it. I click around and ofcourse then lose time. HELP!!!!!!!!!!!!!!!!!

Thanks in advance

Roziea, I had 3 shells to find. The first is a spiny shell that was just above the pictures of items to find. The second was an orangey "round" shell that was just below the key on the left. The third is diagonally up from the key and is a long narrow rifle shell. Hope this helps.