ALCYONOID POLYPS. 89 
or cortex; while the branch on the right, with the surface 
dotted, has the cortex complete, and the dots are the sites of 
the contracted polyps. ‘The circular figure below is a trans- 
verse section of the stem enlarged, showing the cavities occu- 
pied by the retracted polyps. 
In the genus Melitza, and some others related, the inter. 

CORALLIUM RUBRUM. 
nodes are porous and somewhat cork-like or suberose instead 
of horny. ‘The species of this group are often bright-colored 
and much branched, and resemble, in aspect, ordinary Gor- 
gonie ; but they are very brittle, breaking easily at the 
internodes. 
