THE MYRIAPODA. 413 



which is horny, and supports a pair of sharp hooked fangs re- 

 sembling jaws, that move sideways, like the so-called mandibles of 

 the spider. These jaws are, however, only modifications of the 

 first feet, which are converted into' instruments for killing prey, 

 instead of moving their possessor from place to place, and each is 

 perforated near its sharp termination with a long oval slit, through 

 which venom is said to be instilled into the wound inflicted by this 

 formidable weapon. 



The texture of the segments of the body of Julus is hard and 

 brittle, but the rings of the Scolopendra are flattened, and covered 

 above and below with tough and leathery scales. Each segment, 

 as has been stated above, in the Chilognatha, supports two pair of 

 legs on each side on its under surface, but the first three segments 

 only support a single pair. The last two segments are also 

 without legs. The legs are short, feeble, and have several joints. 



In the Scolopendra, however, the legs are long, strong, and very 

 active ; they have five joints, and terminate in a claw. Those 

 attached to the segments near the head are small, but as they 

 approach the hinder part of the body they increase in size 

 and strength, the last pair being turned backwards. The number 

 of the segments and legs appears to be constant in the adult 

 Myriapod, but subject to important and remarkable increase during 

 the progress of growth and development. 



A drawing of the alimentary canal of a Myriapod reminds us 

 of that of the lepidopterous larvae. The oesophagus or gullet of 

 Jiihis terrestris is capacious, the stomach is long and straight, and 

 ends where the liver tubes enter, and an intestine straight and short 

 succeeds. The salivary glands are folded up at the sides of the 

 gullet, and the liver tubes pursue a tortuous course, and terminate 

 at the end of the stomach. In fact, the resemblance is very- 

 great indeed. The respiratory organs are also similar as regards 

 their arrangement in the two classes. The Myriapoda respire in 

 the same manner as insects, by means of lateral spiracles and 

 tracheal tubes. The spiracles are as visible on the sides of some 

 Scolopendrid(B as they are on the flanks of caterpillars, and the 

 tracheae pass inwards in both instances, to be distributed over 

 and amongst the internal organs. Moreover, the minute struc- 

 tures of the tracheae are identical in the two classes, and the spiral 



