Well, never seeing one quite like this and from Austrailia too, I typed in "images of melons" on the web.......I think my search will continue for quite some time.....I may never come up with an answer:):):)

Thanks for trying.

They don't look anything like melons to me, more like seed pods.

I don't think its a melon but Passiflora foetida have a look at the link.

http://www.bio.utexas.edu/courses/bio406d/images/pics/pas/passiflora_foetida.htm

Thank you very much. much appreciated. You are a genius.