1 4 2 MADREPOR ARIA. 



perhaps due to attrition. Similar natural growth-forms are already known, see Goniopora 

 Tonga Islands 3, PI. XI. fig. 7 ; and G. Maldive Islands 3, PI. XIII. fig. 8. 



The top of the stock is irregular, and it is difficult to say whether a sunken patch in the 

 middle of it is natural or artificial. In this patch the calicles are slightly deepened, but the 

 columellar tangle is somewhat raised, and it is possible that the deepening may be due solely 

 to the breaking away of the delicate septa by the forcing in of sand-grains, which are every- 

 where entangled in the meshes of the reticulum. 



This type of calicle, with its lamellated septa, seems to link on best with the group 

 represented by G. Paris Basin 9 and 10, and with the specimens from Coutances, see next 

 page. But the perforations in the septa are so numerous as rather to disguise their lamellate 

 character. In the next coral, on the other hand, the lamellate character of the skeleton is 

 carried to an extreme. 



a. Geol. Pept. R. 4825. 



137. Goniopora Paris Basin (14) 14. (PI. X a . figs. 5, 6, and 8 ; PL XIV. fig. 14.) 

 [? Exact locality ; Eocene ; British Museum.] 



Description. — Corallum small, as a blunt cone apparently built up of two or three 

 colonies, not closely encrusting, that is, of colonies which appear continuous with one part of 

 the stock, but overarch another. In the type specimen the smallest and youngest at the top 

 is free and arching for half its circumference, but continuous with the older growth for 

 the other half. 



The calicles are very deep in the central regions, but are flush with the surface on the 

 downwardly sloping edges of the stock, from 2-2 • 5 mm. in diameter, with marked differences 

 in the characters of the walls. In the deep calicles the wall is a straight, stout, smooth 

 membrane, with an occasional vertical slit, but with hardly any traces of pores, while in the 

 shallow calicles it is a coarse, very irregular, open-meshed reticulum, with hardly any traces 

 of wall-thread except where the two kinds of calicle are passing into one another. The 

 threads of the wall-reticulum are stout, smooth, and obviously form the top edges of vertical 

 membranes, bent and twisted, and fusing together. The septa are very irregular and difficult 

 to count, thick and forking near the walls, on which there are usually some 20 points of 

 attachment. They are conspicuously lamellate and fairly radially arranged, but slightly wavy 

 with jagged sides and granulated top edges ; the lateral points frequently fuse and form a 

 reticulum of threads of varying thickness. The whole reticulum is more delicate the nearer 

 it approaches the edge of the colony. In the deep calicles the septa seldom start from the top 

 edges of the walls, and the knobs or smooth granules along their upper edges are crowded 

 together so that the base of the fossa is a mere irregular mass of minute papillae, which, how- 

 ever, show no traces of symmetrical pali. 



The beautiful little coral above described, with its skeleton built up of smooth vertical 

 lamella}, has the pores of its walls almost obliterated, and, like the last, links on to G. Paris 



