38o 



THE INVERTEBRATA 



gnathochilarium (Fig. 285 C), which, in structure and position recalls 

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



Fig. 285. 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; md. mandible; th. thorax. B, A segment detached from 

 the rest. stm. sternum; tgm. 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.) ch. central body; hyp. hypostoma; /./. 

 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. 



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

 segment. Also a postlabial segment contributes to it forming the 



