Vol. 69.] THE GEXUS AULOPHYLLUM. 55 



these forms did possess a columella. On this ground they created 

 a new genus, Cyclophyllum, and restricted Aulophyllum to forms 

 in which the middle portion of the central column is occupied 

 by tabulae only, and not invaded by the septal lamellae. Their 

 description of Cyclophyllum was as follows (op. cit. p. 32S) : — 



' The corallum is simple, tall, cornute, or more or less cylindrical. The 

 wall is very thin, and is formed of epithecas. The calice is deep, and its margin 

 sharp ; there is a central projection at the bottom of the fossa, separated from 

 the ends of the larger septa by a deep groove. This central mass consists of 

 an endothecal covering, with numerous septa attached to it internally, and 

 coalescing to form some large septa, which ramify over the central depression 

 which represents the top of the columella. 



'The columella is essential, and is made up of laminae which arise from the 

 base of the corallum, and from the dissepiments which unite them. Theendo- 

 theca is largely developed, and the septa are very numerous. There is a fossula 

 with three small septa in it, and a process of the endotheca of the central mass 

 projects into it.' 



The separation appears, at first sight, a very reasonable and 

 desirable one. Closer investigation, however, discloses serious 

 objections. 



The authors state that a columella is essential; but, after a careful 

 study of Thomson's figures published in his'second paper and also of 

 many actual specimens, I am convinced that no columella occurs, 

 not even a pseudo-columella. It is true that the lamellae within the 

 'central mass' (defined by Thomson [12] as 'septa') do coalesce 'to 

 form some large septa, which ramify over the central depression," 

 the result being a network of tissue weakening towards the 

 centre. In most specimens some of the lamellae reach the centre 

 of this inner area; but in *a few cases they all fail to do so, and the 

 Aulophylloid character is produced. This may happen at different 

 parts of the same individual. I am, therefore, compelled to 

 reject the genus Cyclophyllum, and to refer all forms 

 of Thomson's ' Diplocyathophyllidse ' to Aulophyllum. 

 TCunth included a description of the genus as Aulophyllum fungites 

 in his paper on fossil corals (1869) [11], and identified with it 

 Ludwig's species Cyailiodactylia undosa and C. stellata 1 ; but 

 neither the definition nor the figures of these are convincing. The 

 latter, in fact, bear little resemblance to Atdophyllum. 



In 1882 Thomson published a second paper [12] dealing with 

 Cyclophyllum and A%dopJin(llxmi at some length. He embodied in 

 it the conclusions drawn from the examination of over eight hundred 

 sections of Cyclophyllum and twenty sections of Aulophyllum from 

 the Carboniferous Limestone of Scotland. He acknowledged the 

 close relationship existing between his two genera by placing them 

 in a new family, which he called Diplocyatbophyllidae. He, further, 

 cut the original specimen of Ure's Fungites preserved in the collec- 

 tion of the Royal Society of Edinburgh, giving illustrations of the 

 sections (op. cit. pi. ii, figs. 1, 1 a, & 1 b), and described it as Cyclo- 

 phyllum fuvgites, maintaining that it had ' no generic relationship 



1 E. Ludwig, ' Corallen aus PalaolithischenFormationen ' Pakieontographica, 

 vol. xiv (1865-66) pp. 160-61 & pi. xxxvi, figs. 1-2. 



