ROLL C^LL 8:{ 



PHYLUM IV — CTEXOPHORA — Sea-walnuts {Cestus, Hormiphora, Mnemi- 

 opsis) . 

 Characteristics : Eight radially arranged rows of comhjlike plates typi- 

 cally present; fundamentally bilaterally syninictrical; with a distinct 

 mesodermal layer (therefore triploblastic); no nematocysts : 100 species. 



