176 THE NATURALIST IN AUSTRALIA. 
Oligorus gigas or Terra-regine; the Jew-fish, Sciwna antarctica ; the Giant Mackerel, 
Cybium Commersoni; and several of the Yellow-tails, referable to the genus Seriola. 
The extensive family of the Siluridee or Cat-fishes, represented by but a single 
fresh-water species, the Wels or Sheet-fish, Si/urus glanis, in European waters, is a 
conspicuous group in Australia, numbering many species that inhabit both salt and 
fresh water. The detached island-colony of Tasmania is, in fact, the only province 
which is destitute of members. Only one species, the large eel-like Cat-fish, or so-called 
. Tandan,.” of the River Murray, Copidoglanis tandanus, possesses a commercial status, 
and is made the subject of an export trade to the Melbourne and other markets. 
Several allied forms, including other species of Copidoglanis and representatives of the 
genus Plotosus, are nevertheless, and notwithstanding their repulsive aspect and for- 
midable spinous armature, excellent eating. In the tropical districts, the large sea and 
estuarine Cat-fishes of the genus Arius, differing from the preceding in having forked 
instead of eel-like tails, are by no means to be despised for the table when better 
fish are scarce. One species of this group, identical apparently with Arius thalassinus, 
is not unfrequently taken in the neighbourhood of Wyndham, Cambridge Gulf, weighing 
as much as fifty or sixty pounds. All the Cat-fishes are distinguished, as their name 
implies, by the tentacular appendages or barbels which adorn their snouts, and which 
are suggestive of the whiskers, or more correctly the moustaches, of a cat. One of 
the commoner northern species of Plotosus or Cat-fish Eels is represented by Fig. C. 
of Plate XXX. 
There are two fish represented in the Plate last quoted that are very essentially 
Australian. The first of these is Aulopus purpurissatus, Plate XXX., fig. A., known 
to the Sydney fishermen as the “Sergeant Baker.” This local appellation appears to 
have been conferred upon the species with reference to its having been first taken in the 
early days in Sydney Harbour by a sergeant of that ilk. In form, and in its brilliant 
livery of scarlet and purple, the fish is, to a considerable extent, suggestive of a 
gurnet, and is in consequence sometimes invested with that name. As a matter of 
fact, it belongs to the characteristic family of the Scopelide, a group which includes 
the much-esteemed “Bummuloh” or “Bombay Duck,” Harpodon neherens, the deep 
sea Plagiodus ferox, and many singular pelagic and abyssal forms, armed with, in 
relation to their size, most formidable teeth and, in many instances, brilliant phosphoric 
organs. A diagnostic family character, clearly discernible in the photograph of Aulopus 
here reproduced, is the presence of the small dead or adipose fin, like that of a trout, 
situated immediately behind the long dorsal one. The male individual of the Sergeant 
