320 DK. A. VATJGHAN ON THE EAUKAL SUCCESSION [May I906, 



(2) With the Cyathophylla : Cyathophyllum (j> presents a very 

 marked convergence on Liihostrotion cyathophylloides, for 



(a) The characters of septa and vesicles are identical ; and (b) both forms 

 have well-developed tabulae. 



The only independent property in which L. cyathophylloides 

 differs from Cyathophyllum is the elevation of the central portion 

 of the tabulae into tent-like projections, with the necessary accom- 

 paniment of a columellar plate. 



(3) With the Clisiophyllids : The tent-like tabulae of the central 

 area, radiated by prolongations of the primary septa, most probably 

 represent the ancestral character of the Clisiophyllids ; but a true 

 Clisiophyllid always exhibits a differentiation of the radii of the 

 central area into distinct 'lamella?.' Among the Clisiophyllids, 

 Liihostrotion cyathophylloides most nearly resembles Konincko- 

 phyllum. Such a form as Koyiinckophyllum 6 agrees with 

 L. cyathophylloides in : 



(a) The broad external area, completely radiated by the two cycles of 

 nearly-uniform septa and closely packed with fine vesicles ; (b) the 

 elongation of the primary septa towards the centre ; and (c) the 

 columellarian plate. 



Koninckophyllum 6 differs, however, in its higher structural 

 development, as shown by : 



(a) The more numerous vesicles ; and (b) the distinct, if rudimentary, 

 development of lamellae in the central area. 



Clisiophyllttm cuekeenense, sp. nov. (PI. XXX, figs. 2 & 2 a.) 



Description. — Simple corals, of elongate-conical form. 



Horizontal section. — External area: narrow, radiated by 

 both cycles of septa ; the interseptal spaces occupied by a row of 

 four vesicles (or fewer). Inner and outer walls strongly thickened. 



Medial area: radiated by equal, thick, thorn-like primary septa, 

 about 40 in number. The primary septa increase uniformly in 

 thickness outward towards the inner wall. The secondary septa 

 are also thorn-like, and project inward into the medial area for a 

 very short distance from the inner wall. One primary septum is 

 somewhat shorter than the rest, and forms a very inconspicuous 

 septal break. 



Cent ral area: composed of numerous, concentric, tabular inter- 

 sections, which are but slightly broken by the few and feebly- 

 developed lamellae. The outer margin of this area is very open in 

 structure. The columellarian plate is strongly thickened and 

 lentiform ; it is confined to the middle of the area, but, owing to 

 the strong development of one of the lamellae, it is often apparently 

 prolonged towards the septal break. 



Range and variation. — Glisiophyllum curlceenense makes its 

 first appearance in the Megastoma-Be&s. 



