ugly faux-fossil skeleton at left, some signage to the back. The crocodile enclosure is to the right, with a flat viewing window. Inside the little square cave at the back are a couple of pop-up viewing bubbles. There are a couple more viewing windows round to the right out of shot, then you go upstairs and can look down into the enclosure.
See here for a discussion of my visit:
http://www.zoochat.com/24/visit-melbourne-aquarium-22-may-2014-a-365964/
