DIPLOPODA 



423 



a ridged and toothed plate; behind them is an organ known as the 

 gnathochilarium (Fig. 299 C), which, in structure and position, recalls 



Fig. 299. lulus terrestris. A, Side view of anterior end. an. antenna; ah. 

 abdomen ; col. collum (ist thoracic segment) ; e.e. clump of ocelli ; gn. gnatho- 

 chilarium ; g.op. genital opening (on basal joint of 2nd pair of legs) ; hd. 

 head ; Ibr. labrum ; 77id. mandible ; th. thorax. B, A segment detached from 

 the rest. st77i. sternum; tg77i. tergum. C, Gnathochilarium seen from inner 

 side. (The parts — basilar plate — which it is suggested may belong to the 

 segment of the collum are stippled.) c.b. central body; hyp. hypostoma; LI. 

 lamellae linguae; merit, mentum; p.m. promentum; p.p. palps; st. stipes. 

 D, Diagram of four rings seen in side view (above) when the animal is 

 stretched out straight ; (below) when- it is coiled in a spiral. The dorsal part 

 of the ring is clearly seen to be longer than the ventral. A, B and C, original ; 

 D, after Kukenthal. 



the labium of insects and, like it, is formed by the junction of paired 

 appendages, the principal part of it by the appendages of the labial 



