16 Proceed iiuis. 



forms of the Ganoid division are found deep down in the earth, 

 as fossils. They occur in layers of limestone and sandstone 

 which once formed as mud and sand at the bottom of large 

 fresh-water lakes, like the great lakes of America, and which 

 covered sites now occupied by the British Islands. Strange 

 to say, some of the modern forms of these armoured Ganoids 

 are now found in the American lakes. The Ganoids possess 

 ordinary gills with which to breathe, that is, the long pouches 

 or tubes through which the water flowed in the Lancelet, 

 Lamprey, and Shark, and which sufficed to bring the air 

 dissolved in the water into contact with the blood-vessels 

 surrounding those tubes, have for the most part disappeared, 

 and we get what is known as the branchial or breathing-tufts 

 more fully exposed, though they are now protected from out- 

 ward injury by covers or opercula, and present the ordinary 

 form of hsh -gills. 



The next order is a very large one, and embraces a great 

 variety of forms. There is one characteristic, however, runs 

 strongly throughout the group, and as most of our edible 

 fishes belong to this group, we become fully sensible of this 

 feature while eating them. I allude to their bony skeleton, 

 which gives the name of Teleostei, or perfect bones, to the 

 order. Among the large number of these fish I will mention 

 the Perch, with the Indian Perch which climbs up trees, 

 Pike, Salmon, Eel, and Electric Eel among fresh-water fish ; 

 and the Cod, Herring, and Mackerel among marine fishes. 



One subdivision of the Teleosteans contains some curious 

 little fishes, the Sea Horses and Pipe-fishes ; the male 

 Pipe-fish has a pocket in which he carries the eggs about 

 until they hatch. Another subdivision contains the extra- 

 ordinary Globe-fish, or Sea Porcupine, of which I show 

 a specimen, and the common Sun-fish, which sometimes 

 attains the weight of half-a-ton or so. Both these fish have 

 the power of distending themselves with air and floating half 

 out of the water. The pectoral-fin contains four small bones, 

 to which the fin-rays are attached, and these are considered 

 by some naturalists to represent the humerus or shoulder- 

 bone. 



