there is a verse missing from the text for "the oath of bad brown bill", it occurs after the verse which ends 'malodorous and mute' .. and is:

"Then slowly sliding from the trees
And creeping from the deep
The shapes of things long dead and gone
Emerged to blink and peep"

i used to recite this one when i played with an australian "bush band" back in the 80's, audiences loved it .. i remember quietening a packed pub with it one night, much to the annoyance of the publican.