When I was a kid I was walking on the beach and found the skull of a puppy, so decided that I'd collect skulls as I thought they were interesting, but I only ever found one other and that was a sheep's. My Mother refused to let me put it into the car to take it back home (understandably!). So the skull was hardly a collection, but I kept it near my collection of beetles and insects. I kept all the smaller ones in tiny chests made from match-boxes with round paper-fasteners for knobs, and labelled all the ones I could find names for. Now I wonder why one of my grandsons likes collecting things and is a palaeontologist!