78 THE GENUS MONTICULTPORA. 



which Includes forms so Hke Chcptetcs and Monticiilipora in 

 general aspect as to have been commonly included under one 

 or other of the latter heads. Apart from mere superficial 

 appearances — which in this case speak at least as strongly for 

 a Coelenterate as a Polyzoan alliance — there is nothing in the 

 actual structure of Monticiilipora which would not entirely 

 agree with its being a coral. The only point which could be 

 mentioned which would in any fundamental manner distinguish 

 the internal structure of a Monticiilipora from that of, say, 

 Tetradiuni or Heliolitcs, is the absence in the former of septa. 

 I do not, however, attach any weight to this, partly because 

 some undoubted corals are equally without septa, partly because 

 the septa in Hcliolites and its allies are now known by the 

 researches of Moseley to be only " pseudo-septa," and partly 

 because I do not think that any important change in classifica- 

 tion should be based upon a merely negative character. On 

 the other hand, there are strong resemblances between Mon- 

 ticiilipora and its allies and various undoubted corals — prin- 

 cipally, perhaps, the Hclioporidcr. Thus the " tabulae " of the 

 Monticuliporoids are in all respects similar to those of such 

 undoubted corals as Favositcs among the Zoantkaria, and 

 Heliolites among the Alcyonaria. Again, there is the import- 

 ant character that the corallum of the Monticuliporoids can be 

 shown to be so very commonly dimorphic, consisting of two 

 distinct sets of corallites, of different sizes, and mostly with a 

 different internal structure. This last character reminds us 

 so strongly of the Helioporidce — to which there are other men- 

 tionable points of likeness — that I am at present disposed to 

 regard the Monticuliporidce as an ancient group of the Alcy- 

 onaria, at the same time, of course, that I regard the group as 

 a quite independent one, and as quite distinct from the former 

 family. 



