188 ACTINOZOA. 



In some cases the basal deposit encroaches but 

 little on the sides of the corallites ; in others it 

 rises upwards till on a level with their calices, or 

 even above them. Again, instead of remaining 

 horizontal, it may become folded in such a manner 



Fig. 32. 



TuBBiNAEiA PAxiFEBA. Corallum, of the natural size. 



that one part of its distal surface is brought into 

 more or less close contact with the other; the 

 corallites, which previously seemed to arise from 

 the same plane, having now their calices turned in 

 opposite directions. The resulting corallum will be 

 dense or foliaceous, according to the degree of de- 

 velopment of the included coenenchyma, and the 

 greater or less elongation of its projecting corallites. 



Budding from the sides of the corallites takes 

 place, however, more commonly than basal gem- 

 mation, not that the latter must be considered of 

 infrequent occurrence. 



The aspect of the corallum to which parietal 

 gemmation gives rise varies in accordance with 



