170 
by the inter-maxillaries only. Sub-operculum 
absent. Air-bladder generally present, communi- 
cating with the organ of hearing by means of the 
auditory ossicles. Adipose fin present or absent. 
” Inhabitants of the fresh waters of all the tem- 
perate and tropical regions, some entering the salt 
water, but keeping near the coast.” 
COPIDOaLANIS. 
This is the only sort of Siluridce I have yet seen in Australia, 
but several others are described from the Northern Territory, 
and from New South Wales. 
COPIDOGLANIS TANDANUS. 
Plotosus tandanus, Mitchell, Expect., v. i.,p. 95, pi. 6, fig. 2. 
Copidoglanis tandanus, Qunther, Gat., v. p. 26. 
{The Murray Catfish.') 
The colours of this curious fish are subject to the greatest 
changes. Sometimes it is of an olive yellow, lighter on the lower 
parts. On the back are feeble marmorated spots, steel colour . 
head of a fine carmine colour, as also the barbels and pectorals j 
the first dorsal is of a dark olive at its base, and red in the 
other parts ; the second dorsal is also of an obscure olive, bordered 
with red ; the caudal and anal are dark green. In other speci- 
mens, the back is entirely of a brownish black, which extends 
on the sides, and the red tinges sometimes almost disappear ; 
in others again, the general colour is almost white, and the head 
is often yellow. It is almost impossible to find two specimens 
entirely alike. 
This sort appears to be common in the Murray and in the 
rivers of Eiverina ; it is brought to Melbourne, at times, princi- 
pally in winter, by the Echuca Eailway. It is considered good 
food, and attains two feet in length. The fishermen of the 
Murray distinguish three sorts — the white, the black, and the 
blue, but I think they only constitute varieties of colour. 
