456 THE INVERTEBRATA 



The chilaria, as has been stated, are the appendages of the pre- 

 genital segment. They are flattened processes without any function 

 that has been discovered. 



The appendages of the opisthosoma are shown in ventral view 



Fig. 336. Limulus polyphemus, x J. Ventral view. Slightly altered from 

 Shipley and MacBride. an. anus; chc. chelicerae; chi. chilaria; g.op, genital 

 operculum (7th appendage) ; M. mouth, surrounded by gnathobases ; opi. 

 opisthosoma; pp. pedipalps; tel. telson or caudal spine; 3-6, prosomatic 

 appendages; 8-12, exopodites of opisthosomatic appendages. 



(Fig. 336), and vertical longitudinal section (Fig. 329). They are all 

 greatly flattened and expanded , consisting typically of a slender ' ' endo- 

 podite" and a broad plate which is the "exopodite". The anterior pair 

 arise in the embryo as distinct rudiments, but fuse to form the genital 

 operculum, on the under surface of which are the genital apertures. 



