30- 



ARACHNIDA SCORPIONIDEA 



longi- 



eyes of Limulus. The arrangement of various slight 

 tudinal ridges on the dorsal surface of the carapace is of systematic 

 importance. On the ventral surface, just in front of the genital 



, Pedipalp 

 Lateral eyes 

 '' Afetiian. eyes 



,ster/Lum 



aculem-s. )/ 'vesicle 

 Fig. 169. — Buthus occitanus. A, Dorsal view ; B, ventral view. (After Kraepelin.) 



and sometimes barely 

 one of the principal 



operculum, is a sternum, never large, 

 visible. Its shape and .size constitute 

 family characteristics. 



Mesosoma. — The dorsal plates or terga are distinct, and are 

 connected by soft chitin with their corresponding sterna. 



Beneath the second abdominal segments are borne the 

 "pectines*' or comb - like organs. In their structure four 

 portions are distinguishable, an anterior lamella or shaft attach- 

 ing them to the body, a middle lamella, the teeth, and the 

 fulcra, a series of small chitinous pieces intercalated between the 

 bases of the movable teeth. 



