486 INVEHTEBRATE MORPHOLOGY. 



In Scutigera, a form whicli frequents the warmer parts of 

 the world, the dorsal surface of the body is covered in by 

 eight shieldlike folds which conceal a certain number of the 

 segments, which are about fifteen in number. Lithobius has 

 the same number of segments and is common under stones, 

 etc., as is also Geophilusand Scolopendra, both elongated forms, 

 the former usually without eyes, while the latter usually 

 possesses them but has only some nine or ten pairs of stig- 

 mata. Some of the species of iScohpendra, especially those 

 living in warm countries, grow to a considerable size and are 

 capable of inflicting a dangerous wound. 



4. Order Symphyla. 



The order Symphyla contains a number of small forms 

 referable to one or two genera, of which the best known is the 

 genus ScolopendreUa (Fig. 224). Unfortunately the details of 

 the structure of the members of the group are by no means 

 well known, a circumstance all the more to be regretted since 

 ScolopendreUa seems to possess certain Insect-like features. 

 The body is elongated, and on the dorsal 

 surface possesses a number of plates 

 which overlap slightly, but which do 

 not correspond in number with the ap- 

 pendages. The head bears a pair of 

 long many-joiuted antennae, and behind 

 these, in the region of the mouth, is a 

 pair of mandibles and a single pair of 

 maxillsB, both these last-named ap- 

 pendages being deeply imbedded as it 

 were in the tissues of the head, their 

 Fig. 334.'- ScolopendreUa *ips °^1.T projecting. The first pair of 

 immaculaia (from lbunis). trunk appendages is not transformed into 

 maxillipeds as in the Chilopoda, but is 

 ambulatory in function, and most, but not all, of the succeed- 

 ing segments, of which there are apparently fourteen, bear a 

 pair of five-jointed legs terminated by two claws. Attached 

 to the coxal joints of most of these appendages is a peculiar 

 spurlike process, internal to which is situated a protrusible 



