2868 



THE BONY FISHES AND GANOIDS 



present; and the air bladder is simple. The ovaries are in the form of plates, and, 

 in the absence of a duct, the eggs fall into the abdominal cavity. The species of 

 the typical genus, which, although devoid of scales, are externally very similar in 

 appearance to trout, are confined to the lakes and rivers of Chili and the extreme 

 south of Patagonia and the Falkland islands. In South Australia and New Zealand 

 the family is represented by the genus Prototroctes , in which the body is scaled and 

 the jaws are armed with minute teeth; the New-Zealand species being commonly 

 known to the colonists as the grayling. 



THE SALMON TRIBE Family SALMONID^ 



With the salmon tribe, which include the finest and ' ' gamest ' ' of all fresh- 

 water fish, we come to the last group of the true bony fishes, which may be 

 distinguished from the preceding family by the margin of the upper jaw being 



ZEBRA SALMON. 



formed by the premaxillse in front and by the maxillae at the sides. As a rule, the 

 body is scaled, while the head is invariably naked, the under surface of the body 

 being rounded. Inhabiting alike salt and fresh waters, those species which spend 

 a part or the whole of their existence in rivers or lakes are in the main confined to 

 the Temperate and Arctic zones of the Northern Hemisphere, although one out- 

 lying genus occurs in New Zealand; and whereas the majority of the marine forms 

 are deep-sea fishes, two genera are entirely pelagic in their habits. A considerable 

 number of the species inhabiting fresh waters descend periodically or occasionally 

 to the sea; and in some cases it is perhaps rather difficult to say whether these 

 fishes should be regarded as marine or fresh water. All the salmonoids are remark- 

 able for the excellent quality of their flesh, which in many forms is of a more or less 

 strongly-marked pinkish hue, brought about by the crustaceans on which these 



