FISH AND FISHERIES. 31 



6. Plectognathi. — A soft dorsal fin opposite to the anal ; sometimes 

 the elements of a spinous dorsal. Ventral fins none, or reduced to spines. 

 Gills pectinate. Air-bladder without a pneumatic duct. Skin with 

 rough plates or shields, or with spines, or naked. 



Such a large number of existing fishes are included in the first order 

 that no less than nineteen divisions are made by Dr. Giinther. As, 

 however, only a portion of these are found in Australia, it will be better 

 to proceed at once to the characters of the families, or at least such as 

 New South Wales is interested in. The first which occupies our attention 

 is the family of Percidse or Perches, which is thus characterized : — 



First Division. — Acanthojiterygii. — Perciformes. — Body more or less 

 compressed, elevated, or oblong, but not elongate ; vent remote from the 

 extremity of the tail, behind the ventral fins if they are present. No 

 prominent anal papillje. Dorsal fin or fins occupying greater portion of 

 the back ; spinous dorsal well developed, generally with stiff" spines of 

 moderate extent, rather longer than or as long as the soft ; the soft anal 

 similar to the soft dorsal, of moderate extent or rather short. Ventrals 

 thoracic, with one spine and four or five rays. 



These features are shared by ten families, of which five at least are 

 important to the fisheries of New South Wales.* 



I— Fam. PERCID^. 



Scales I'arely extending over vertical fins, lateral line generally present, 

 continous from the head to the caudal. All the teeth simple and 

 conical, no barbels. No bony stay for the operculum. 



This family is veiy large, and consists of carnivorous fishes, which are 

 distributed all over the world. Fossil genera belonging to Austi'alia 

 are found in European tertiary formations, such as Lates, Dules, S'erramcs, 

 and it is not improbable that they may be found in this Colony also. 

 One of our commonest fishes is Lates colonorum, Giinth. The genus 

 is distinguished by a compressed body, viliform teeth, teeth on tlie 

 palatine bones, none on the tongue, no canines. Two dorsal fins, the 

 first with seven or eight, the anal with two spines. Preoperculum with 

 strong spines at the angle of the lower limb, preorbital strongly 

 serrated. 



The Perch. 



(Plate I.) 



Lates colonorum, the perch of the colonists, is easily distinguished by 

 its continuous dorsal fin, which according to Macleay should remove it 

 to another genus. The fourth spine in the dorsal fin is the longest, 

 third anal spine a little longer than the second, lateral line slightly 

 curved. Colour silvery, darker on the back. 



* It must here be mentioned that the arrangement followed in the essay is that 

 of Gunther's latest work on the Study of Fishes, and differs in the grouping from 

 that adopted by the Blue Book E,eport of the Commissioners on our Fisheries. 

 The difference, however, is very trifling. 



