770 



ARTHROPODA 



THYLUM VII 



•fo«^ Some of these, however, may be suppressed during 

 :rorgi;;nTÄ är Absang t« *« adult «tage, 0. el.e be_g 



fused in v.irious ways. r, •/!„ ^„a crrmmpd to^ether in hi2;her aggregates 



The body Segments o^^Anjchmd ar g^rou^^^^^^^^^^^^^ g^^^^ ^ ^^ 



hanJ 



L.ätera1 eyes 

 ,■ 'Median e/es 



esosoma 



S fern am 



qenital 



•^ operculut 



T 



•I 



■A/ers 



Fig. 1496. 



Duthus uccitanus Amoreux, a typical Old-World Scorpion, A, Dorsal, and B, ventral view. 



1/3 (after Kraepelin). 



metasoma (another name for the " postabdomen " or " tail " of earlier writers, 

 Fig. 1496). The first of these regions includes all of the segments in front 

 of the genital pore, usually six in number. The second, or mesosoma, begms 

 with the somite bearing the genital pore, and ends with the last somite which 

 bears free appendages, typically six segments in all. The third region, or 

 metasoma, consists usually of six segments, none of which bear appendages, 

 excepting that the terminal one often has attached to it a postanal " telson, 

 which may be considered as in the nature of an appendage. The latter takes 

 in Scorpions the form of the sting, in Xiphosures and Eurypterids that of the 

 spine. Among Merostomes, where the body is sometimes sharply divided 

 functionally into two regions only (" cephalothorax " and "abdomen" as 



