SPIDER-LIKE ANIMALS 



389 



Fig. 236. Book-Scorpion (Cheli- 

 snlarged. Natural 



of the abdomen by two pairs of stigmata. Spinning glands open 

 on the chelicerae, and the simple eyes, two or four in number, are 

 situated on either side of the front of the head. 



A common European species is the little Book - Scorpion 

 (Chelifer cancroides) (fig. 236), often found in old books and 

 similar dark places. 



Order 4. WHIP-SCORPIONS (Pedipalpi) 



The Whip -Scorpions make up a small 

 but widely-distributed order, the members of 

 which are fairly large in size. They are 

 found in the warmer parts of both hemi- 

 spheres, and considerable interest attaches to 

 them, owing to the fact that they are in some 

 respects intermediate between Scorpions and Spiders, on which 

 account they are sometimes called Scorpion- Spiders. A typical 

 Whip- Scorpion (Thelyphonus) looks not unlike a real Scorpion, 

 the pedipalps being large and provided with pincers, and the 

 abdomen narrowed into a sort of tail, reduced, however, to a 

 mere filament. The breath- 

 ing organs are lung-books 

 (two pairs), and the eyes are 

 arranged in a central and 

 two lateral groups. Among 

 the important differences 

 from Scorpions may be 

 noted chelicerae provided 

 with claws, not nippers, 

 modification of the first 

 pair of legs into tactile 

 organs, and distinct mark- 

 ing off of the abdomen. 



Some of the other genera 

 (as Phrynus] (fig. 237) ap- 

 proximate more closely to the Spiders, for the pedipalps possess 

 claws instead of pincers, and the abdomen is joined to the rest 

 of the body by a narrow waist. The tail filament is only repre- 

 sented by a button-like knob. 



Fig. 237. A Whip-Scorpion (Phrynus). a, Front of 

 cephalo-thorax, enlarged to show eyes. 



