PLATE I. 



Coencecium of Cephalodiscus dodecalophus, about the natural size ; a few of the branches 

 terminate in somewhat flattened tips. At a, one of the pillars, which like aerial 

 roots pass downwards to the stones and sponges on which it grows, is represented, 

 its tip being expanded into a broad surface. Numerous inosculations take place 

 between the various branches. 



