1 66 TABULATE CORALS. 



covered by an epitheca (?). The corallites are firmly united 

 by their walls, which are extensively perforated by apertures 

 which place the visceral chambers of contiguous tubes in direct 

 communication. Septa trabecular, often irregularly divided, or 

 anastomosing at their free ends. Tabulae rudimentary, repre- 

 sented only by occasional horizontal trabeculse. No columella, 

 nor ccenenchyma. 



Obs. This genus is founded upon a remarkable specimen 

 belonging to the " Daintree Collection " of corals, from the 

 Devonian or Carboniferous deposits of Queensland, descrip- 

 tions of which will shortly be published by Mr R. Etheridge, 

 jun., and myself. Pending the publication of our joint memoir, 

 I shall simply avail myself here of the permission of my col- 

 league to briefly discuss the characters and affinities of the 

 genus Arceopora, as deduced from the only species with which 

 we are as yet acquainted, and which we propose to name 

 A. Aiistralis. 



The corallum in our specimen of Arczopora Australis might 

 at first sight be taken for that of any of the larger and more 

 massive species of Favosites (such as F. hemispherica, Yand. 

 and Shum.) ; though even to the naked eye the absence of dis- 

 tinct tabulae and the cribriform or porous condition of the walls 

 are striking features. The height of the specimen (which is 

 an imperfect one, and is not only silicified, but is likewise thor- 

 oughly infiltrated with silica) is rather more than three inches,, 

 and its greatest width something over four inches. Its form 

 is pyriform, the narrow base having evidently been attached 

 to some foreign body, while the under surface was almost cer- 

 tainly covered with an epitheca, of which no traces now remain. 

 The calices must have opened over the whole of the convex 

 upper surface, but none of them are preserved in the example 

 before us. The corallites radiate with a graduated divergence 

 from the imaginary axis of the colony, and their form is reg- 

 ularly prismatic or polygonal, as in Favosites. This character 

 is much more perceptible to the eye, or when the surface is 

 examined with a lens, than it is when thin sections are inves- 



