j 2 8 THE ANIMAL KINGDOM. 



obtain the air, which is dissolved in the water in which 

 these gills float gracefully. 



Myriapoda* are so called from their possessing a 

 very great number of feet certainly not a myriad, but still 

 enough to have given rise to a name which must be taken 

 to mean many-footed. In these animals we find the rings 

 broader and much stiffer than in the bodies of worms ; 

 they vary in number, but are never less than twenty-four. 

 They have a distinct head, furnished with eyes, mouth, 

 and feelers ; all the other segments of their body are 

 alike. They breathe by means of minute pores, called 

 spiracles, placed all along the sides of their bodies, and 

 from these innumerable tubes, called trachea, convey the 

 air over the entire system. They are divided into Mille- 

 pedesf which have the greatest number of legs; but 

 these legs are not jointed, but bristle-like, as in worms 

 and the Centipedes, \ which have fewer legs, but 

 these are jointed like those of insects. 



The Millepedes feed on decayed vegetable matter, and 

 are perfectly harmless ; the Centipedes are carnivorous, 

 and some of them have a painful and poisonous bite. 

 When the young Myriapods first emerge from the egg, 

 they are quite without legs ; but in a few days they cast 

 their skin, and have three pairs. They keep on changing 

 their coat, each time obtaining additional pairs of legs, 

 until they are fully grown-up. 



Insects. This wonderful class of Articulata the 

 members of which are so varied in their forms and 

 habits are so numerous, that it will only be possible in 

 this small book to give the barest description of their 

 leading features. True Insects arc formed in three seg- 

 ments (i) the Head, with the horns or antenna ', and the 



* Myriad-footed. % A hundred feet. 



t A thousand feet. Insectum, divided into segments. 



