AULOPORID^. 225 



crossed at right angles by numerous delicate cross-bars or tra- 

 beculae of sclerenchyma (fig. 32, E and F). This extraordinary 

 reticulate tissue is present in the calicine wall of all specimens 

 of Monilopora crassa which have hitherto been examined, but 

 no similar structure is known to occur in any other coral, nor 

 does it seem possible to offer any probable suggestion as to its 

 functions or homologies. Apart from this unprecedented fea- 

 ture, Monilopora can only be separated from Aulopora by the 

 total absence of tabulae, such as exist in, at any rate, some of 

 the latter, if not in all. 



As to the affinities of the Auloporidce, it appears hazardous 

 at present to give any definite opinion. If I am right in refer- 

 ring Syringopora to the Perforate Corals, then it would not 

 appear that the present group can have any real alliance with 

 the Syringoporidce ; and its relationship with any other division 

 of " Tabulate Corals " would seem to be even more remote. 

 Perhaps the most probable conjecture is that which would look 

 upon the Auloporidcz as a peculiar group of the Alcyonaria. 



