240 



MANUAL OF ZOOLOGY 



SECT. 



fused segments. The antenna consist sometimes of many, 

 sometimes of comparatively few seg- 

 ments. A pair of eyes, situated on 

 the dorsal surface of the head, con- 

 sist of aggregations of ocelli except 

 in Scutigera, in which there are com- 

 pound eyes, differing, however, in 

 their structure from those of insects. 

 There are in millipedes a movable 

 labrum, a pair of mandibles, and a 

 pair of fused maxilla. In the cen- 

 tipede there are three pairs of jaws 

 in front of the poison- fangs. The 

 mandibles have no palps ; one or 

 both pairs of maxillae usually possess 

 palps. 



The number of segments in the 

 body varies from 12 to 173. In the 

 millipedes (Diplopoda) the dorsal 

 walls of the segments are very 

 strongly arched ; in the centipedes 

 (Chilopoda) the segments are all 

 dorso-ventrally compressed, with dis- 

 tinct tergal and sternal shields 

 (scuta) separated laterally by inter- 

 vals of comparatively soft skin on 

 which the stigmata open. In the 

 centipede each segment bears a pair 

 of jointed legs ; of these the most 

 anterior pair is extended forwards 

 to form a pair of poison-fangs, at 



FIG. 140. Scoiopendra, orcen- the extremity of the pointed ter- 



tipede. (FromCuvier's/l- .... / i i i j 



imai Kingdom.-) minal joint of which opens the duct 



