138 MADREPOKARIA. 



wall-ridges are very sharp. It is impossible to say for certain into what these young colonies 

 would have developed. The synapticular proliferation on their septa is exactly like that 

 above described ; the flaky coluinellar tangle is absent in the smaller colony, but begins to 

 appear in the larger. 



These are the last of the specimens showing the curious synapticular proliferation of the 

 septa. The next forms are, however, nearly as remarkable, but do not admit of being arranged 

 into series, as the essential character of the specialisation is not so easily perceived. 



a.-c. Geo. Dept. E. 4820. 



132. Goniopora Paris Basin (14) 9. (1*1. X. fig. 9 ; PL XIV. fig. 11.) 

 [? Exact locality ; Eocene ; British Museum.] 

 t Litharaa Heberti, M.-E. & H., Nat. Hist. Coralliaires, iii. (1860) p. 187. 



Description. — Corallum lens-shaped, with smooth surface. The successive edges not 

 bending far under the circumference of the stock. 



Calicles only faintly distinguishable in the loose, open reticular skeleton, about 3 mm. in 

 diameter. Slightly and irregularly depressed. The walls rise so irregularly that they nowhere 

 form continuous ridges and are thus very inconspicuous. Closely examined the wall-thread is 

 seen to be thin, but slightly thicker than the septa, and to form only fragments of a wavy 

 rather than zigzag boundary to the calicles. the waves or angles being so large and the thread 

 so interrupted that the wall seems to have dissolved into the loose open-meshed reticulum. 

 The septa are very wavy, not of uniform thickness, and are joined irregularly by thin 

 synapticular ; the number and arrangement of the septa is quite irregular and obscure. A few 

 large, open, interseptal loculi are generally present ; the large gaps in the wall enable them to 

 run into those of adjacent calicles. The columellar tangle is variously developed, the tapering 

 edges of the septa forming sometimes an open large-meshed reticulum, not sharply defined 

 from the rest of the intracalicular skeleton. 



The surface aspect suggests that the skeletal elements are all lamellate, but in the section 

 hardly any lamellae can be seen, but thin wavy vertical trabecular separated by large oval 

 pores, so that the stock is very light but not friable, for the elements are all fairly thick. 



This specimen was tentatively labelled Litharcea Heberti M.-Ed. and H. Its walls are 

 certainly not distinct, but it can hardly be said that the calicles are polygonal, for their 

 boundaries seem to have dissolved away, and further, none of the really important features 

 in this coral are noted in Milne-Edwards' description. For an extreme development of this 

 type of structure cf. G. Coutances £, p. 144. 



a. Geol. Dept. R. 4821. 



133. Goniopora Paris Basin a 4 )10. (PI. X°. figs. 1 and 2.) 

 [Auvers (Upper Eocene) ; British Museum.] 

 Description. — Corallum massive, in large blocks, original shape of which is unknown. 

 Calicles, 2 mm., rather deeply concave, subcircular, with very thin, sharp wall-thread 



