ANTHOZOA. ZOANTHARIA 81 



found inside the calyx of the parent — hence this is known 

 as calicular budding (fig. 26 B). In basal budding (fig. 

 26 C), which is rare in the Madreporaria but common in 

 the Alcyonaria, the buds spring from creeping prolonga- 

 tions or stolons, which are given off from the base of the 

 coral. Fission, or division into halves, commences by the 

 mouth becoming slightly constricted in the middle ; this 

 increases until two distinct mouths and two polyps are 

 formed, after which a similar division takes place in the 



Fig. 27. Section of a dissepiment of Galaxea. Magnified, g, growth- 



lamellas. (From M. M. Ogilvie.) 



skeleton. When the individual corallites in a compound 



form are free and diverge from one another, the corallum 



is termed dendroid (fig. 26 A) : when they are in contact, it 



is massive. If the corallites are not in contact the spaces 



between the individual corallites are sometimes filled up 



with calcareous material formed by the coenosarc, and 



known as coenenchyma. In many compound corals (e.g. 



Acervularia) the base of the corallum is covered by a thin 



epithecal plate — the basal epitheca. 



In dendroid corals (fig. 26 A) the polyps on the different 



corallites may be quite separate from one another ; but in 



massive corals, whilst the upper parts of the polyps are 



w. p. ,. 



o 



