VI 



APPENDAGES OF SCORPIO 



interest as showing the very first beginning of the modification of an 

 appendage for purposes of mastication — the basal segments (Fig. loo, II) 

 being especially stout and strong, being attached to the body in close 

 proximity to one another, and being movable in such a way as to be 

 squeezed together and crush any food substance between them. The 



fil.r^'-<- 



Fig. gg. 



A Scorpion. B, ventral view. I, Chelicera ; II, pedipalp ; III-VI, walking legs ; (VII, missing 

 in adult) ; VIII, genital operculum ; IX, pecten ; X-XIII, openings of lungs. /., Telson. 



succeeding two pairs of appendages (III and IV) are also adapted for 

 mastication, but here the specialization has gone a step further, the basal 

 segment of each projecting forwards as a stout blade, with a cutting edge 

 on its mesial side, which can be brought against its neighbour like the 

 blade of a pair of bone forceps. The seventh appendages, corresponding to 

 the chilaria of Limulus, are completely absent in the adult, but it is 



