FISHES OF AUSTRALIA. 



CHAPTER I. 

 INTRODUCTION. 



General definition of Fishes The principal parts of a Fish The 

 Teeth The Air-Bladder The Eyes The Tongue The Skeleton 

 The Fins The Scales The Lateral-Line Barbels Colouration 

 Breeding Habits and Eggs Australian Fishes producing Pelagic 

 Eggs The Classification of Fishes Table of Classification of 

 Australian Fishes. 



FISHES, defined in a popular way, are aquatic, vertebrated 

 or backboned animals ; cold-blooded and breathing by 

 means of gills. They are provided with fins, to assist 

 them in guiding or propelling themselves through the 

 watery element by which they are surrounded, and in 

 which their whole existence is passed. "It is in their 

 conditions of living," writes Bashford Dean, "that they 

 have differed widely from the remaining groups of verte- 

 brates. Aquatic life has stamped them in a common 

 mould, and has prescribed the laws which direct and limit 

 their evolution ; it has compressed their head, trunk, and 

 tail into a spindle-like form ; it has given them an easy 

 and rapid motion, enabling them to cleave the water like 

 a rounded wedge. It has made their mode of movement, 

 one of undulation : causing the sides of the fish to contract 

 rhythmically, thrusting the animal forward." 



In the body of a fish, four parts are usually distin- 

 guished : the head, the trunk, the tail and the fins. 

 The head is usually divided from the trunk, by the gill- 

 is 



