SCORPIONS 71 



curved and pointed. Its base is enlarged and contains a pair of 

 poison glands which open near the tip. On the ventral side of the 

 abdomen, immediately behind the genital opercula, is situated a 

 pair of comb-like organs known as 'pectines' which are not found 

 in any other animals. Each pectine articulates with a chitinous 

 plate representing the second sternite and is provided with com- 

 plex musculature. Its components form three longitudinal series. 

 Of these the back is composed of three parts, the proximal being 

 the longest, while the lamellae or teeth comprise the third series 

 and are inserted between the constituents of the median row. 



Genital 

 plates 



-• Pectine 

 Stigmata 



Fig. 18. Ventral view of a scorpion showing pectines. 



These lamellae vary in number from three to more than forty 

 depending upon the sex and species of the scorpion, and are 

 richly supplied with nerves. 



The dorsal surface of the prosoma is covered by a compact and 

 unsegmented shield or carapace which bears a pair of median and 

 from three to five pairs of lateral simple eyes. The mouth is ventral 

 in position and is situated between an anterior and a posterior lip. 

 In front and above the base of the pedipalps are a pair of short 

 chelate chelicerae used for mashing and shredding the food, while 



