66 CORALS 



of a great deal of care and patience, and many difficulties 

 have usually to be overcome owing to irregularities in growth. 



It cannot be expected that any one would care to deter- 

 mine the orders of sequence of the septa unless he were 

 specially interested in the group, but it is of importance for 

 the student of corals to understand that the general prin- 

 ciples of septal sequence are manifest in Fungia with its 

 hundreds of septa, as in other Madreporarian corals with 

 septa that can be more easily recognised and counted. 



The most important point to notice in the study of the 

 septa of this coral, however, is the presence of the svnapticula. 

 It is important because the synapticula form one of the 

 characteristic features of the family and because in Fungia 

 they are larger and more easily studied than in any other 

 genus. The synapticula are bars of coral substance that 

 pass from one septum to another at regular intervals, binding 

 the septa together and giving rigidity and strength to the 

 coral as a whole. As a rule the synapticula do not appear 

 near the upper regions of the septa but are more or less 

 hidden in the depths of the interseptal spaces. They can 

 usualty be seen, if the specimen is not too massive, by holding 

 the coral in front of a strong light, or, for more careful study, 

 by filing down the septa of a part of a spare specimen until 

 they are reached. 



It may be an open question whether in Fungia there is 

 a true columella. The fossa is usually deep and at the 

 bottom of it there is a plexus of calcareous trabeculae which 

 may be regarded as a rudimentary columella. 



The single large polyp that gives rise to this coral has a 

 slit-shaped mouth in the centre of the disc above the fossa, 

 and it is surrounded by an enormous number of long tentacles 

 slightly inflated at the extremity. It might seem at first 

 sight that the tentacles are indefinite in number and irregu- 

 larly scattered over the surface of the disc, but a careful 

 study of the hard and soft parts has shown that each tentacle 

 is situated on a slight elevation close to the innermost edge 

 of a septum and that consequently the tentacles have the 

 same orderly sequence as the septa and are arranged in 

 regular cycles. The soft fleshy body wall of the polyp covers 



