GENERA OF CH.ETETIDAi AND MONTICULIPORID.E. 265 



as seems all but absolutely certain. At the same time, I see 

 no reason whatever for accepting the view, advocated at the 

 present day by high authorities, that Chcetetcs is not truly a 

 Coelenterate. I am quite unable to recognise in the structure 

 of the fossils referred to this genus anything which would 

 justify us in referring them to the Polyzoa (as advocated by 

 Lindstrom and others), and I think the general details of their 

 structure to be such as are only compatible with their being- 

 members of the Coelenterata. The precise position which they 

 should occupy among the Actinozoa is a point upon which it 

 is far more difficult to arrive at any positive conviction. Upon 

 this point, while confessing the absence of positive evidence, I 

 can only say that I am disposed to agree with Professor Martin 

 Duncan (Third Rep. on Brit. Foss. Cor. ; Brit. Ass. Reports, 

 1 87 1, p. 128) in thinking that Cho'tctes is probably an Alcy- 

 onarian. 



As to the relations of Chcetctes to allied genera, it can only 

 be said at present that there is nothing save close external 

 resemblance to unite the genus with any other, and especially 

 with the group of which Monticttlipora is the central type. 

 For reasons previously given, I have not thought myself 

 justified in definitely separating the species of the latter from 

 Chcetctes, with which they often agree in general form and habit, 

 as well as in the imperforate walls of their corallites ; but I 

 entertain at the same time a strong conviction that there 

 is little or no true affinity between the two. Most of the 

 so-called Moiitiailiporce, apart from other peculiarities, have 

 heteromorphic coralla, composed of two distinct sets of 

 zooids, and in all of them the walls of the corallites are 

 not amalgamated with one another. These distinctions alone 

 are quite sufficient to fundamentally separate the typical forms 

 of Monticulipoi^a from Chcstetes. The type with which Chcetdes 

 shows the strongest affinity is the Silurian Tetradiumi but in 

 this genus we have well -developed and definitely- disposed 

 lamellar septa, and we can therefore hardly suppose that 

 the two genera are closely related. 



