368 



PHYLUM ARTHROPODA 



be said that the centipedes (Chilopoda) and the miUipedes 

 (Diplopoda) are very closely related to one another, and 

 there are two other distinct orders, Symphyla and Pauro- 

 poda. The resemblances are in part resemblances of 



I 



n.c 



Fig. 208. — Mouth-parts of a millipede. — From a Specimen. 



I. Mandibles. IIa. Outer blade (exopodite) of first maxilla. IIb. Inner blade 

 (endopodite). lie. Basal piece or protopodite of first maxilla. 



convergence, not of genuine affinity. Simple wingless 

 insects, known as Collembola and Thysanura, are closely 

 approached by such Myriopods as Scolopendrella ; and it 

 is likely that Myriopods and Insects are divergent branches 

 from a common stock. 



Centipedes and millipedes are characteristically terrestrial . 

 Most are very shy animals, lurking in dark places and 

 avoiding the light, but it is interesting to note that at 

 least two Myriopods — Geophilus submarimis and Linotcenia 

 maritima — occur on British coasts. 



