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TEXTBOOK OF ZOOLOGY 



atus are fairly common in many parts of the United States. In the 

 family Polydesniidae, Polydesmus serratus Say is a common species 

 in the United States west to the Mississippi River. 



Members of the class Chilopoda differ from the Diplopoda by their 

 dorsoventrally flattened bodies, consisting of fewer segments which 

 bear but one pair of legs, and by their long antennae. The Chilopoda, 

 as a rule, move faster than millepedes. 



The Chilopoda are carnivorous, preying upon adult as well as im- 

 mature insects, also upon spiders and Mollusca. The mouth parts 

 consist of a pair of mandibles and two pairs of maxillae. A pair of 



Fig. 165. — Scutigera forceps. The long-legged house centipede. (From a paper by 

 C. L. Marlatt, Farmer's Bulletin, No. 627, U. S. Dept. of Agriculture, 1914.) 



poison claws are located on the first body segment, the last two seg- 

 ments are legless, and each of the other body somites bear a pair of 

 seven-jointed walldng legs. 



The circulatory system is well developed ; it extends the full length 

 of the body and gives off in each segment lateral vessels or arteries. 



The nervous system consists of connected paired ganglia in each 

 leg-bearing somite and a subesophageal and supra-esophageal ganglia 

 which supply nerves to the eyes, mouth parts, antennae, and other 

 parts of the head. 



