I was cleaning out my pool with a leaf scoop the other day and found a small object, which I assume to be a sort of skull or cartilaginous structure of something that had died.
I live in Sydney, Australia and in the pool there were a large quantity of water boatmen and dragonfly nymphs.
What does this skull belong to, and what is the purpose of the hollow, bulbous mounds next to the eye sockets?
