FISH AND FISHERIES. 381 
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 Percidss or Perches, which is thus characterized :— 
First Division.—<Acanthopterygut.—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 papille. 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. PERCIDE. 
Scales rarely 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 very large, and consists of carnivorous fishes, which are 
distributed all over the world. Fossil genera belonging to Australia 
are found in European tertiary formations, such as Lates, Dules, Serranus, 
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 the 
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 colonorwm, 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 Giinther’s latest work on the Study of Fishes, and differs in the grouping from 
that adopted by the Blue Book Report of the Commissioners on our Fisheries, 
The difference, however, is very trifling. 
