CHMTETID& AND MONTICULIPORID^E. 255 



proper we have only the forms which properly constitute the 

 genus CJuztetes, Fischer (as typified by C. radians, Fisch., and 

 exclusive of the Monticuliporce). These forms possess corallites 

 of one kind only, which are completely amalgamated by their 

 walls, and which possess comparatively few and remote tabulae. 

 In the other group we have all the forms included under the 

 genera Monticulipora, D'Orb., Fistiilipora, M'Coy, Dekayia, 

 E. and H., Const ellaria, Dana, and Prasopora, Nich. and Eth., 

 jun., in all of which the walls of the corallites are not fused 

 with one another, and there is mostly the important feature 

 that the corallum is composed of two distinct classes of coral- 

 lites, indicating the existence during life of two distinct kinds 

 of zooids. The corals of this latter group I shall speak of 

 collectively as the Monticuliporida, though I do not at present 

 feel justified in finally removing them from the vicinity of the 

 Chcztetidce proper, as there are a few forms generally referred 

 to Monticulipora in which the corallites are homomorphic, and 

 in which the corallum only differs from that of Chcetetes^ in its 

 most restricted sense, in the fact that the corallites are not 

 united by their walls. 



As regards the affinities of the Chcetetidce and Monticuli- 

 poridce anything that can be said at the present moment can 

 be regarded as, at best, little more than conjecture. So far as 

 Ch&tetes proper is concerned, I do not at present see that we 

 have any sufficient ground for supposing that we have to deal 

 in it with anything but a group of genuine -Actinozoa. The 

 association of Chcetetes with the true Favositida, as proposed by 

 Milne- Ed wards and Haime, must certainly be rejected, as there 

 is no evidence to hand of the existence of perforations in the 

 walls of the former, and there are other important differences as 

 well. At the same time, the general structure of Chcetetes is 

 entirely that of the Corals rather than of the Polyzoa, and there 

 is a very close resemblance to such forms as Tetradium, Saff,, 

 the only essential difference between these two types being the 

 possession by the latter of definite septa. When, however, 

 we come to ask more particularly as to the precise place of 



