138 FISHES OF AUSTRALIA. 



widespread species ; and amongst other localities, is occa- 

 sionally obtained on the Queensland coast. On its 

 grotesque-looking head immediately in front of the eyes, it 

 possesses a curious horn-like projection, which is sometimes 

 as much as 2 inches in length. The fish itself attains a 

 length of upwards of two feet. 



The principal Surgeon-Fish on the New South Wales 

 coast, is that known as Prionurus microlepidotus. It is one 

 of those species possessing the row of keeled plates on each 

 side of the tail, and is rather a funereal-looking fish, being 

 of a uniform dark colour almost black. This fish is a 

 rock-dweller and subsists largely on gelatinous seaweeds. It 

 is occasionally taken by hook and line in the vicinity of 

 Sydney Heads, but is more-usually captured in the trammel- 

 net. 



It reaches a length of about 18 inches. 



THE "BLACK TREVALLY" FAMILY. 



(Family: Siganidce) 



OF this family about 30 species are known from various 

 parts of the Indian and Pacific Oceans. They are all char- 

 acterised by the possession of a strongly-compressed oblong 

 body, covered with very small scales, and may be readily 

 recognised by the singular structure of the fins. In all of 

 the species, the dorsal fin has 13 spines and 10 rays; while 

 the anal fin has 7 spines and 9 rays. It is well to make a 

 note of this, as it is of great assistance in recognising these 

 forms. The ventral fin has a very curious structure indeed, 

 possessing an inner spine as well as the outer one usually 

 seen in fishes, with three soft rays in between. All the 

 spines of these fishes are very acute ; and wounds inflicted 

 with them have been found to be very painful. This applies 

 equally to the species found along our own coastline. 



All of these fishes are vegetable- feeders and they are 

 nearlv all of small size. 



