226 
In the three smallest specimens the axial fossa has not yet 
divided itself into secondary calicles, but they are easily disting- 
uishable from young specimens of Fungia echinaia by their smaller 
costal spines and their granulate smaller septa (figs. 66—69). 
Adult specimens of F. echinata are usually much broader than 
specimens of Herpolitha simplex of about the same length. Unfor- 
tunately two of my larger specimens have broken in the long axis 
and afterwards regenerated, in normal specimens the length would 
exceed that given in the table above. 
Herpolitha weberi (van der Horst) 
Fungia iveheri van der Horst 1921. 
This species is not represented in my material, but some parti- 
culars of it may be dealt with here, as the species is an inter- 
mediate form between Herpolitha simplex and H. Umax. 
In the description of this species, based on two broken speci¬ 
mens from Stat. 315 of the Siboga Expedition, van der Horst 
already States that in several points of the original axial fossa two 
opposite septa have fused across it. This process of fusion is quite 
the same as in young specimens of Herpolitha Umax and results 
in the formation of secondary calicles. A comparison of Gardiner’s 
figure of Herpolitha foliosa (1909, PI. 36, fig. 15) with the figure 
of Fungia iveberi (van der Horst 1921, PI. I, fig. 5) shows at first 
sight that the fusion of the opposite septa in each of the two 
species leads to a similar formation of secondary calicles. 
In this species there is a strong growth-tendency in the direc- 
lion of the long axis; nearest to the anterior (or posterior) septum 
of the first cycle a great many septa of higher cycles have been 
added which have not yet developed in the lateral parts of the 
corallum. The number of cycles cannot be determined, for each of 
the two specimens has regenerated from less than a half of a 
broken corallum, which may be concluded from the direction of 
the septa. In the regenerated parts new mouths have developed 
each with a number of septa the central parts of which are more 
or less radially arranged round their centre. 
In the longer specimen of H. weberi there are, besides the 
calicles in the axial fossa, the first traces of secondary calicles in 
the lateral parts of the corallum. In some places one of the more 
