252 



MANUAL OF ZOOLOGY 



SECT. 



no palps ; one or both pairs of maxillae usually possess 

 palps ; the second pair of maxillae are in some groups more 



or less united together. 



The number of segments in 

 the body varies from 12 to 173. 

 In the Millipedes the dorsal 

 walls of the segments are very 

 strongly arched : in the Centi- 

 pedes the segments are all dorso- 

 ventrally compressed, with dis- 

 tinct tergal and sternal shields 

 separated laterally by intervals of 

 comparatively soft skin x?n which 

 the stigmata open. In the Cen- 

 tipedes each segment bears a 

 pair of jointed legs ; of these 

 the most anterior pair is ex- 

 tended forwards to form a pair 

 of poison-jaws (maxillipeds), at 

 the extremity of the pointed ter- 

 minal joint of which opens the 

 duct of a poison-gland. In the 

 Millipedes each segment behind 

 the fourth or fifth bears two 

 pairs of legs, the four or five most 

 anterior segments having only one 

 pair each. In most of the Mil- 

 lipedes and their allies the ap- 

 pendages of the seventh segment 

 are modified in the male to form 

 copulatory organs. 



The enteric canal is straight, 

 FIG. 139. Centipede (Scolopen- . 



dra). (From Cuvier's Animal and is much simpler in char- 



Kingdom.) 



