This strange jellyfish was floating/swimming in the shallows at Lee Point. I expected to see box jelly fish and instead saw this amazing disk. After a lot of research I think it might be a jelly fish in the Order of Rhizostomatida. Detailed info on the marine world of the Arafura Sea seems to be limited to commercial interests and therefore is not located on the public domain.
I was lucky enough to see a small flock of Blue-faced Honeyeater Entomyzon cyanotis Subspecies:albipennis, comprising two adult birds and three offspring. They were eating insects and upon a close encounter noticed the blue around the eyes. The juveniles had a more greenish eye colouring.
It is found in north Queensland, west though the Gulf of Carpentaria in the Northern Territory and across into the top of Western Australia, with white on the wings and a discontinuous stripe on the nape. [http://en.wikipedia.org/wiki/Entomyzon]
The Blue-faced Honeyeater is one of the first birds heard calling in the morning, often calling 30 minutes before sunrise.[http://www.birdsinbackyards.net/finder/display.cfm?id=154]