30 NEW SOUTH WALES 



CHAPTER III. 



Our Marine Food Fishes. 



The study of fishes, were it only in an economical point of view, is of 

 the greatest importance and interest. As articles of food, though but 

 one of the uses of fishes, they must even command our attention, yet 

 their value in this respect is hardly appreciated. Fish is known to be a 

 light and easily digested diet, but it is not known that it contains as 

 much protein a^ pork, and consequently 100 lbs. of fish contains as much 

 nourishment as 200 lbs. of wheaten bread and 700 lbs. of i^otatoes. This 

 encouraging fact may well awaken our interest sufliciently to enable us 

 to get over the following dry technicalities which are a necessary key to 

 the comprehension of the subject. 



It "will be borne in mind that fishes are divided into four sub-classes, 

 viz. : — Teleostei, Fakeichthj/es, Cyclostoviata, and Le])toca7-dii. Each of 

 these sub-classes are divided into orders and sub-orders. Each of the 

 orders are separated into divisions, and these again into families. The 

 families are made up of similar genera, and the genera comprise one or 

 more distinct species. It is very difficult for the mind to grasp these 

 distinctions at once, because their number becomes so bewildering. It 

 will facilitate the comprehension of these methods if we suppose the 

 class fishes to represent a kingdom ; the sub-classes, the counties ; the 

 divisions, the parishes ; the families, the villages or towns ; the genera, 

 the houses ; and the residents, the species. 



Sub-class TELEOSTEI. 



Heart with a non-contractile arterial bulb, optic nerves crossing, intes- 

 tine without spiral valve, skeleton bony, vertebrte completely formed, tail 

 generally homocercal. 



This sub-class is divided into six orders : — 



1. Acanthojiterygii. — Part of the rays of the dorsal, anal, and ventral 

 fins composed of non-articulated spines. The lower pharyngeal bones 

 separate. The air-bladder in the adult without a pneumatic duct. 



2. Acanthopterygii pharyngorjnathi. — The same features as the last, 

 but the pharyngeal bones united. 



3. Anacanfhini. — Vertical and ventral fins without spinous rays. 

 "Ventral fins (if present) jugular or thoracic. Air-bladder (if present) 

 without pneumatic duct, lower pharyngeal separate. 



4. Fhysostomi. — All the fin rays articulated ; only the first of the 

 dorsal and pectoral fins is sometimes ossified. Ventral fins if (present) 

 abdominal and without spine. Air-bladder (if present) with a pneumatic 

 duct. 



5. Loj^hohranchii. — Gills not laminated, but composed of small 

 rounded lobes attached to the branchial arches. Gill cover reduced to 

 a large simple plate. A dermal skeleton replaces the more or less soft 

 integuments. 



