THE ANIMAL KINGDOM. 



.frog is given in Fig. 77; and from this you will observe 

 the small number of bones in the spine, and also the 

 entire absence of ribs. 



PISHES. 



FISHES are vertebrate animals whose whole construction 

 is adapted for life in water; they have red, cold blood, 

 and are born from eggs. The heart consists of two 

 chambers only. The limbs are replaced by fins, and the 

 body is covered either by bony plates, which form a com- 

 plete armour, as in the Trunk Fish or Ostracion, of the 

 Red Sea (Fig. 78), in which the plates are so firmly united 

 that a box is formed with openings through which the 

 tails and fins project ; or by scales, which in some fishes, 

 as the Salmon (Fig. 83) and the Carp (Fig. 84), are flat 

 and round, whilst in others they are more bony, and of 

 various shapes some so small and so embedded in the 

 skin as to be scarcely perceptible at all. 



The outward form, as well as the internal structure of 

 fishes, is suited to their aquatic life ; the body being 

 flattened, generally vertically, but sometimes horizontally ; 

 there is no neck, the head, neck, and chest being united 

 in a continuous form. 



Fishes breathe by means of gills, of which there arc 

 generally four on each side, each composed of double 

 rows of plates. They are fringe-like, membranous plates, 

 fixed on the edge of bony arches, and in these the blood 

 circulates and receives the oxygen which is dissolved in 

 the water which enters at the mouth, and, after bathing 

 the gills, passes out at the opening of the gill-covers. 



The Anabas, or Climbing Perch, has a receptacle to 

 contain water for moistening the gills ; it can therefore 

 leave the water, and travel along the bank some say, 

 climb a tree, by aid of spines on its chin, gill-covers, &c. 



