PHYLUM ARTHROPODA 



261 



ing by gills, in which the body consists of two regions, — the 

 cephalothorax and the abdomen. The former is covered 



cejbh 



cjberc 



Fig. 157. — Ventral view of Limulus. /-6, appendages of cephalothorax; abd, 

 abdomen; ceph, cephalothorax; operc, operculum, behind which are seen the 

 series of abdominal appendages; tels, caudal spine or telson. (From Packard, 

 after Kingsley.) 



over by a broad shield or carapace, bearing two large com- 

 pound and two smaller, simple eyes. The segments of the 



