Vol. 67.] THE AVONIAN OF BURR1NGTON COMBE. 379 



Occurrence. — Endophyllum burringtonense occurs in Z., and y 

 at Burrington, and the y forms are markedly larger than those 

 from Z . The same form occurs in the Rush Slates of County 

 Dublin and in y of Malahide. 



Cyathophyllum. 



Cyathophyllum (?) 6 Vaughan. (PI. XXXI, fig. 2 : a calicular 

 view.) 



A horizontal section of a young form is figured in the Bristol 

 Paper, pi. xxiii, fig. 2. It is much easier to describe this striking 

 coral than to assign it to a particular genus. 



In the adult, there is an external ring of fine vesicles, crossed 

 by equally distinct major and minor septa. 



The major septa extend to the centre, where they become 

 flexuous, and one of them is strengthened to form a conspicuous 

 ridge. 



The walls of the calyx descend steeply from a sharp rim ; the 

 floor of the calyx is vaulted in the middle to form a tall conical 

 peak, crested by the strengthened septum. As remarked above, 

 the long septa climb this peak somewhat spirally. 



The earliest stage has no vesicles and presents a Caninoid type 

 of septation. 



The fossula is strongly developed at all stages on the Caninia- 

 like plan. 



As a mere description, Cyathophyllum appears to be more 

 satisfactory than Caninia, since it implies the actual plan of the 

 septation and the biseptate external ring of vesicles ; furthermore, 

 Cyathophyllum murchisoni frequently exhibits a fossula precisely 

 like that of our species. That the species had a Caninoid ancestor 

 seems, however, clear. 



The elevation of the peak is extremely variable, though always 

 noticeable. The external form is a typical, wide-angled horn, and 

 the epitheca is nearly smooth. The vertical section shows clearly 

 the incoming of the vesicles, at some little distance from the tip. 



This species occurs at only one level within y. I know it from 

 other points of the South-Western Province, but never from any 

 other horizon ; it is common at Burrington. 



I owe the fine figured calyx to Mr. H. F. Barke, of Bristol, who 

 extracted the coral from a mass of limestone by immersion in 

 acid. 



Cyatuophyllum murchisoni Ed. & H. (PI. XXXI, fig. 6.) 



This section suggests relationship to the Diphypliyllum figured 

 in the same Plate (tig. 7) ; but the resemblance is deceptive and 

 accidental. The two rings of fine vesicles separated by a ring of 

 more open texture, are at once determinative of Cyathophyllum, and 

 the central tabulate area is an abnormality confined to a portion 

 only of the individual. This kind of abnormality is even commoner 

 in the simple forms of Cyathophyllum regium, in which there are 



2d2 



