EASTERN LONG NECKED TORTOISE Chelodina longicollis (Shaw, 1794)
This tortoise can attain 30 cm, although most adult specimens average 15-20 cm in length. It's dorsal shell(Carapace) colour can vary from all black through all shades of brown to almost white with well defined darker lines around the scutes.
The species is found throughout south east and east Australia. Specimens from coastal areas tend to have darker narrower shells than those from the Murray/Darling river system. Found in most water systems and major fresh water bodies within its' range including small creeks. Although an opportunistic feeder, this species shows a strong preference for frogs and snails. During summer major overland migrations may occur.
Egg laying occurs in spring and early summer, when the female tortoise deposits 4-12 soft shelled eggs in an excavated hole adjacent to the water where the tortoise lives. These usually hatch in autumn, but sometimes mid winter, (100-200 days later).
The young tortoises are usually brightly coloured with black shell and orangish markings which fade with age. This is the type of tortoise most commonly kept as a pet in eastern Australia.

The above was from the book Australian Reptiles and Frogs by Raymond Hoser and now available on a fantastic CD-Rom along with a vast amount of other information, papers and the like on reptiles, frogs and other wildlife.