FISH AND FISHERIES. 105 
they stretch across the river at night, thereby intercepting fishes passing down 
the river. If, as mentioned above, these river fishes have their migratory periods, 
the complete stoppage of the river by nets may be most injurious or even 
destructive to them.—R.R.C. 
The Freshwater Black-fish. 
A very common fish in some of our rivers, both of eastern and 
western waters, is the ‘ Black-fish,” Gadopsis marmoratus, which 
belongs to a genus of the most extraordinary fishes known. It is, 
according to Professor M‘Coy, an intermediate type between the 
Acanthopterygious fishes, in which the anterior rays of the dorsal fin are 
simple spines, with the scales usually ctenoid, and the Malacopterygious 
fishes, in which all the rays are soft and branched, and the scales usually 
cycloid. In Gadopsis the cycloid scales, the general form, the imperfect 
filamentous jugular ventral fins, and the majority of the characters so 
* nearly agree with Malacopterygions that all the most recent writers with 
Dr. Giinther class it with the Anacanthini, although the anterior rays of 
the dorsal and anal fins are distinctly spinous: Our species is a mud 
fish, and attains the length of 16} inches, but it is generally caught by 
emptying the water-holes where the summer heat has made them low. 
It is good eating, but like all these mud-fishes, very rich and oily. In 
G. marmoratus, Richardson, the head is one-fourth of the length. 
Prof. M‘Coy has described two species. One, G. gracilis, in which the 
head is proportionately much shorter. ‘This is found in the river Yarra, 
and differs in its habits from the fish of western waters, as it is readily 
caught with a line. It is alsoa far better fish for the table, and is 
much esteemed in Melbourne. 
There is a second species of Gadopsis (G. gibbosus, M’Coy), which is 
proportionately shorter, deeper, and with a much more convex dorsal 
outline. It abounds in the Bunyip River, Gippsland, Victoria. Another 
distinction is that it has twelve instead of ten spines in the dorsal. The 
colouring of these fishes is very variable. Some are light olive green, 
becoming yellowish-white towards the belly, the sides, back, and fins being 
mottled irregularly with dark brown. This marbling varies from brown 
to olive in smaller or larger patches, and the yellow varies to orange. 
It is only when the mottling is very dark and thick that the name 
Black-fish is at all applicable. Sometimes the brown marbling is slight 
and distinct, and the general colour yellowish olive. The scales vary 
also from truly cycloid to an indented margin, and undulating lines of 
growth approaching the ctenoid type. An excellent figure of G. gracilis 
is given in M‘Ooy’s “ Prodromus of the Zoology of Victoria,” decade 
3, plate 27, fig. 2. The name Gadopsisis meant to mean like the cod 
or Gadus. 
The Freshwater Cat-fish. 
The ‘‘cat-fish” (Copidoglanus tandanus) is very abundant in the lagoons and 
back waters of the western rivers, and is said to be a most excellent fish, but 
there is a very general prejudice among Europeans against its use: it is very fat 
and eel-like in Raver, and averages, when full grown, 2 feet in length. In this 
species, as in most if not all of the Siluride, the ova are fertilized by the male 
fish before leaving the body of the female, and both sexes seem to unite in the 
subsequent attendance on the nest in which the ova are deposited.—R.R.C. 
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