Fig. 12 — Transverse section of polypary of 



Coppinia arcta for correlation with crust of 



Hydractinia (Fig. 7), and the section of stem 



of Antennularia (Fig. 13). 



(a). — Zoophyte stem, upon which Coppinia arcta is parasitic. 



(b). — Horizontal cells or tubes (?), from which arise the 

 vertical tubes c. 



(c). — Vertical polypite tubes. 



