508 



ARACIIXIDA. 



eleven segments and no jointed anal filament. Ph. rcniformis Latr., in Brazil. 

 Thelyplionus Latr. The chelicerae are short and end in a chela, their masti- 

 cating blades fuse in the middle line. The elongated twelve-ringed abdomen 

 with segmented anal filament. T. caudatm Fabr., in Java. 



Order 6. SCORPIONIDEA* (SCORPIONS). 



Arachnida with chelate chelicerce, and elongated, pediform chelate 

 pedipalpi, with a prat-abdomen composed of seven segments, and an 

 elongated post-abdomen of six segments, with poison spine at the hind 

 end ; with four pairs of lungs. 



The Scorpions have a cer- 

 tain resemblance to the De- 

 capod Crustacea in their 

 powerful chelate pedipalpi and 

 firm armour (fig. 410). The 

 stout cephalo- thorax is joined 

 to an elongated abdomen, 

 which is divided into a cylin- 

 drical prse -abdomen, composed 

 of seven segments, and a very 

 narrow six-segmented post- 

 abdomen, which is curved 

 dorsalwards. The post-abdo- 

 men ends with a curved poison 

 spine, which is provided with 

 two poison glands. The cheli- 

 cera? are three -jointed and 

 chelate; the pedipalpi end 

 with a swollen terminal 

 chela, while the basal joint 

 serves with its broad grinding 

 surface as a jaw. The four 

 pairs of legs are strongly de- 

 veloped and end with double 

 claws. 

 In their internal organization the Scorpions reach the highest 



* P. Gervais, " Remarques sur la famille dcs Scorpions et description de 

 plusieurs especes nouvelles, etc." Arch, du muxee d'liixt. -nat., IV. Newport, 

 " On the structure, relations, and development of the nervous and circulatory 

 Systems in Myriapoda and macrourous Arachnida," Phil. Tra/is. 1843. 

 L. Dufour, " Histoire anatomique et physiologique des Scorpions," 3fem. pres 

 a Vacad. dcs sciences, XIV., 1856. E. Metschnikoff, " Embryologie dcs Scor- 

 pions," Zeitschr fur mifd., Zool. t 1870. 



FIG. 410. Cephalo-thorax and prre-abrlornen of 

 Scorpio africanus (rcgne animal). Kf, Cheli- 

 cerag ; Kt, pedipalpi ; Z", pectines ; St, 

 stigmata. 



