NO. 10 l-i:iiDJN(.; ORGANS or AKACllNllJA- -SNOIKIRASS 39 



tissues of the prey. Diirin<^ t'ccding the soft-skimicd larva thus 

 alternately expands antl contracts according to whether it is being 

 injected with the solvent liquid or exhausted by suction. Though 

 Chclifcr is classed by Chambcrlin as a genus having a venom gland 

 in each fnigcr of the chelae, Schlottke says no poisonous effect was 

 to be observed on the captured prey. 



\'[I. TIIH S("ORPIONII).\ 



\\ ith the scorpions more parts o{ the animal's .'uiatomy have been 

 brought into the service of the feeding function than in any other 

 arachnid. Tiiere is present the usual association of the chelicerae, 

 the labrum, and the pedij^alp coxae, but the under lip of the scorpion 

 is composed of endite lobes from the coxae of both the first and the 

 second pairs of legs, the pedipalps bear strong chelae, and, in addition 

 to these structures, the postabdominal tail with its sting plays an 

 important role in the feeding process by the subduing of prey caught 

 and held in the pedipalp chelae. 



The relatively small, three-segmented chelicerae ot the scorpion 

 jjroject straight forward from beneath the overhanging edge of the 

 carapace (fig. 13. A). They are turned on their sides so that the 

 movable linger of each a]ipendage has a lateral position. In Ccnlrtt- 

 roidcs this linger is deeply cleft into two points (I^, C), which clasp 

 the immovable finger when the pincer is closed. The pedipalp chelae 

 of the scorpion have been sufficiently described in the General Discus- 

 sion (p. 14, fig. 5 D, E, F), in which the identity of the segments 

 composing the chela was deduced from a comparison with the struc- 

 ture and musculature of the legs ; the "hand" of the chela is the 

 tibia, the movable finger is the tarsus, with possibly the tip derived 

 from the pretarsus. 



Conspicuous at the anterior end of the scorpion's body is a large, 

 open, quadrate cavity (fig. 13 D, PrC) between the flat mesal sur- 

 faces of the pedipalp coxae {IICx), covered above by the flattened 

 chelicerae {Chi), and closed below by the closely apprcssed endite 

 lobes of the coxae of the first and second legs (II Hindi . Il'Endt). 

 This cavity is evidently a receiving chamber for food material crushed 

 by the pedipalp chelae and further comminuted by the chelicerae. 

 Concealed within it is the labrum, and below the latter the mouth, 

 both being fully exposed on removal of the chelicerae and the pedipalps 

 (E). The labrum (I^m) is a large, soft, laterally compressed lobe 

 with a rounded dorsal wall terminating in a fringe of long hairs (G, 

 Lm), below which the anterior labral wall recedes to the short ventral 



