292 PERIPATUS, MYRIOPODS, AND INSECTS. 



The development in many ways suggests and leads up to 

 that of Insects. 



MYRIOPODA. 



A pair of appendages to each 

 segment. 



Many-jointed antennae. 



Toothed cutting mandibles. 



Each maxilla consists of an ex- 

 ternal palp, and a bilobed median 

 portion. 



The next appendage is leg-like. 

 Then follows a large basilar plate, 

 beside which are the two poison 

 claws. 



A single posterior genital aper- 

 ture. 



Examples Scolopendra. 

 Lithobius. 



By the imperfect separation of the 

 segments all but the most anterior 

 seem to have two pairs of append- 

 ages each, and also two paired 

 ganglia, and two pairs of stigmata. 



Seven-jointed antennfe. 

 Broad masticating mandibles. 

 Maxilla; are represented by a 

 four-lobed plate. 



No basilar plate. 



Genital apertures open on the 

 second or third pair of limbs. 



Examples — -Jnhis. 



Geophibis. 



In reference to habitat, it is interesting to note that at least two 

 myriopods — Geophihis siibmariiuis and Linctccnia inaritiina, occur on 

 British coasts. 



As distinct from the two chief sub-classes, it is perhaps necessary to 

 recognise other two — Pauropoda, e.g., Panroptis, and Symphyla. e.g., 

 Scohpendrella. The last-named approaches closely to the most primi- 

 tive insects (Collembola and Thysanura). 



Third Class of Tracheata Antennata. Insect.^. 

 Insects occupy a position among the backboneless animals 

 like that of birds among the Vertebrates. The typical 

 members of both classes have wings and the power of true 

 flight, richly aerated bodies, and highly developed nervous 

 and sensory organs. Both are very active and brightly 



