190 



SYSTEMATIC ZOOLOGY 



dorsoventrally, sometimes circular in cross section. There is a 

 head made up of several fused segments, succeeded by a large 

 number of distinct segments, essentially all alike, and each, with 

 the occasional exception of the last, bearing one or two pairs of 

 jointed appendages, each of which terminates in a claw. The 



head bears two many-jointed antennae, 

 several pairs of eyes, and from two to three 

 pairs of mouth parts. The most anterior 

 pair of mouth parts is usually very strongly 

 developed and called the mandibles ; the 

 succeeding pairs are known as the first 

 and second maxillae. The anus is terminal. 

 The stigmata are few in some cases, but 

 usually there is a pair to each segment of 

 the body. The eggs are deposited in the 

 earth and often develop into a larva, which 

 has only a few segments and fewer pairs 

 of appendages ; it moults repeatedly, 

 gradually increasing the number of seg- 

 ments and of appendages. The Myria- 

 poda are commonly divided into two 

 orders, though two others, each comprising 

 a single genus, are often recognized. 



Order 1. Chilopoda 



The Chilopoda (Gr. ^et\o?, lip, and 7rou?, 

 foot) are commonly called centipedes (Fig. 

 1 87 ), and have the body distinctly flattened 

 dorsoventrally. They vary greatly in size, 

 in the tropics sometimes attaining a length 

 of twenty-five centimeters or even more. 

 The antennae have at least twelve joints 

 and in some species are as long as the 

 whole body. There are three pairs of 

 mouth parts and on each segment of the 

 trunk — -there are sometimes over a hundred segments — a single 

 pair of appendages of seven joints. The first pair of trunk 

 appendages, just posterior to the mouth, is modified into two 



FIG. 187. Scolopendra, a 

 centipedf. (From Cuvier's 

 Animal Kingdom.) 



