FRENCH GONIOPORA. 135 



bore, oval, and from 3 to 4 mm. long-diameter, while the third specimen (c) did not completely 

 surround the object which it encrusted. 



Michelin named the coral Astrcca ame/iana, because Defrance* described two specimens 

 Tinder this name, one of which, from some unknown locality, might have been a spherical 

 form of this coral (showing no trace of attachment), while the other, "found at Grignon," wu 

 apparently quite typical. The latter differed from the former in being slightly " spongy." 

 Defrance speaks of this latter as occurring also at Hauteville and Orglandes (La Manche), 

 and as being found attached to Cerithium cornucopia (= Campanile giganteum). See above, 

 G. Paris Basin 2. 



In the same year (1826) Goldfuss t described and figured a specimen as Astrcea muricata, 

 which seems to represent this coral, but he says nothing about any hole through it. He 

 speaks of it as being found beautifully preserved in the chalk at Meudon. Michelin 

 emphatically denied that his coral occurs there. We have at first sight no means of deciding 

 whether Goldfuss was mistaken as to the locality, or whether there is another of these remark- 

 able forms actually found in the chalk at Meudon. For the present, however, we are justified 

 in assuming that this kind of Goniopora, which is peculiar to the Paris Basin, could hardly 

 have been developed in Cretaceous times, and that therefore Goldfuss was in some way 

 misled. 



The incipient proliferation of synapticular points at the sides of the septa, already noted 

 in G. Paris Basin S, is here rather more freely developed. We shall find it carried still 

 further in the next form to be described, in which it reaches an extreme. 



The specimens fall easily into three stages, c, a, b, in the production of this unique 

 specialisation, on the probable cause of which see under the next form, and the Eemarks to the 

 French fossils, p. 145. 



Specimens a-c were presented by Professor Milne-Edwards to the Museum of Practical 

 Geology, and afterwards transferred to the British Museum Collection. 



Geol. Dept. & 4817. 



128. Goniopora Paris Basin (14) 5. (PI. X. fig. 5 ; PI. XIV. fig. 9.) 

 [Probably Chaussy and Middle Eocene ; British Museum.] 



Description. — Corallum forms small convex masses, being built up by rapid continuous 

 growth, with a few edges ; extremely light and friable. 



Calicles from 3-3 • 75 mm. across ; shallow concave. Walls of varying thickness, here 

 and there sharp thin ridges ; but often broad as light flaky foams. The septa are 24 and show 

 signs of the typical formula ; but this is obscured by the proliferation of synapticular points 

 into jagged flakes running out in all directions, not only horizontally (cf. next form). The 

 columellar tangle is very large, and at the surface consists of an elegant open angular 

 reticulum of delicate filaments. 



The light, spongy, vertical section of this beautiful coral suggests very rapid growth in 

 thickness. The flakes of the reticulum are not by any means all horizontal, and the meahet 

 are slightly drawn out vertically. Both the extreme lightness of the specimen and also the 



* Diet, des Sci. Naturelles, xlii. (1826) p. 384. 

 t Petr. Germ., i. (1826) p. 71, pi. xxiv. fig. 3. 



