AL'JYONOID 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 Melitsea, and some others related, the inter- 



CORALLIUM RTTBRTJM. 



Lodes are porous and somewhat cork-like or subereous instead 

 of horny. The species of this group are often bright-colored 

 and much branched, and resemble, in aspect, ordinary Gorgon- 

 ia) ; but they are very brittle, breaking easily at the inter- 

 nodes. 



