SCORPIONS. 329 



it has been answered that they do not sting themselves, that 

 they could not if they would, and that, even if they could, 

 the poison would have no effect ! 



The body is divided into (i) a cephalothorax or "pro- 

 soma " of six segments, whose terga fuse into a carapace, and 

 (2) an abdomen which includes a broad seven-segmented 

 " mesosoma," and a narrow five-segmented " metasoma." 

 At the end of the latter there is a post-anal curved spine or 

 "telson," containing a paired, compressible poison gland 

 opening at the sharp tip. There is a strong cuticle of chitin, 

 and also an interesting internal piece of skeleton (the endo- 

 sternite), partly chitinoid, but also resembling fibro-cartilage, 

 which lies in the cephalothorax above the nerve cord, and 

 serves for the insertion of muscles. 



The appendages are 



(i.) Small three-jointed chelate chelicerre or fakes just above the 

 mouth, used in holding prey. 



(2.) Large, six-jointed, chelate pedipalps. These seize the prey ; 

 their basal joints help in mastication, and in some cases they produce 

 rasping sounds. 



(3-6.) Four pairs of seven-jointed, non-chelate walking legs. The 

 basal joints of the first two pairs help in connection with the mouth. 



Apparently equivalent to a first pair of abdominal appendages is a 

 small notched plate or operculum which covers or bears the genital 

 aperture or apertures. 



Apparently of the nature of appendages are the comb-like, probably 

 tactile, pectines on the second abdominal segment. 



Six other pairs of abdominal appendages are present in the embryo, 

 but they abort. 



The nervous system consists of a dorsal brain, a ring 

 round the gullet, and a ventral nerve cord. The simple 

 eyes situated on the carapace are innervated from the 

 brain, the first six appendages from the collar and the sub- 

 oesophageal ganglion. Behind the latter there are seven 

 ventral ganglia in the eleventh to seventeenth segments 

 inclusive. 



Scorpions seize small animals with their pedipalps, hold 

 them close to the small mouth by their chelicerae, sting them 

 if need be, and suck their blood and juices. The pharynx 

 serves as a suction pump, a narrow gullet leads to a slight 

 enlargement, into which a pair of salivary glands open ; from 

 the narrow mid gut several large digestive outgrowths arise ; 



