INTRODUCTION. 15 



number of Fishes." And certainly this is borne out in 

 our experience with Australian fishes ; many of which are 

 possessed of the richest and most glorious colours ; colours 

 which in the fresh fish absolutely beggar description. 



The Breeding Habits of Fishes : Most fishes repro- 

 duce by means of eggs ; though many bring forth their 

 young alive. Amongst the Teleosteans, viviparous fishes 

 are seldom met with, the principal number being amongst 

 the Plagiostomes (Sharks and Rays). Fish-eggs are 

 generally divisible into two kinds ; pelagic and demersal. 

 Pelagic eggs are distinguished by their lightness and 

 buoyancy so that they float ; usually at the surface of the 

 sea. (In some kinds, the specific gravity is such, that the 

 eggs, while not floating at or near the surface, will re- 

 main suspended at a considerable depth in the ocean.) 

 Pelagic eggs are usually of exceedingly small size and are 

 remarkably transparent. A prominent feature in many of 

 them, is the presence of a single, comparatively large, oil 

 globule, on the surface of the yolk, while in others, two 

 or more globules may be present. Eggs of a pelagic 

 nature are never found in fresh- water; belonging solely 

 to marine fishes. The reason which is, perhaps, suffi- 

 ciently obvious is that if the eggs of river fishes were 

 to float, they would in many cases be swept out to sea and 

 destroyed. 



Amongst the Australian fishes, at least the following 

 species produce pelagic eggs: 



Sergeant Baker (Aulopus purpurissatus) . 

 Skipper Garfish (Scombresox forsteri). 

 'Sea Mullet (Mugil dobitla). 

 Flat-tail Mullet (Mugil peronii). 

 Yellow-eye Mullet (Agonostomus forsteri}. 

 Blackfish (Girella triciispidata). 

 Estuary Perch (Percalates coloiiorum). 

 Cuvier's Sea Perch (Hypoplectrodcs nigrorubrum) . 

 Sand Whiting (Sillago cilia ta). 

 Trumpeter Whiting (Sillago maculatd). 

 Snapper (Pagrosoinns auratus). 

 Black Bream (Chrysophrys australis). 



