654 



ZOOLOGY 



SECT. 



External features. A Scorpion (Fig. 533) has a long narrow 

 body, in superficial appearance not unlike that of a Crayfish. 

 There is a small cephalothoracic shield or carapace, covering over 

 dorsally a short anterior region, eepkalothorax or prosoma. This 

 is followed by a long posterior region or abdomen, the terminal 

 part of which in the living animal is habitually carried over the 

 back (536), constituting the " tail," at the end of which the sting 

 is placed. The carapace bears a pair of large eyes about its 

 middle, and several pairs of smaller eyes on the antero-lateral 



FIG. : :,. Euscorpio. (From 

 Cuvier's Animal Kingdom.) 



a 



,ped. 



FIG. 534. Scorpion. Ventral surface of the 

 ceplialothorax and pre abdomen, chel. cheli- 

 ceras ; op, operculum ; pect. pectirres ; ped. 

 pedipalpi ; stig. stigmata. (From Leuckart 

 and Nitsche's Diagrams.) 



margin. The anterior, broader part of the abdomen, which is 

 termed the pre-abdomen or mesosoma, consists of seven segments, 

 each of which is enclosed in firm, chitinous, dorsal and ventral 

 plates, or terga and sterna. The tergum and sternum of each 

 segment are separated from one another laterally by intervals 

 of soft skin, except in the seventh, where they are united laterally 

 for a longer or shorter distance. The posterior, narrower part of 

 the abdomen, known as the post-abdomen or metasoma, consists of 

 five segments, each enclosed in a complete investing ring of hard 

 chitinous matter. Articulating with the last segment of the 



