28 



BRANCH CCELEXTERATA 



Fig. 18. — Athc'lla iiiirdh'iUs. Ciencral view of branch. View of a calice. 

 (Vaughan, in Bull. U. S. F. C, 1900.) 



Fig. 19. — Favia fragum (Esper). View of a corallum from the side. 

 (Vaughan, in Bull. U. S. F. C, 1900. j 



retracted tentacles until it looks like a round mass of flesh. The 

 tentacles are hollow and are armed with lasso cells, which are 



