6 BRITISH FOSSIL CORALS. 



collections of the Geological Society of London, and of MM. Searles Wood, Bowerbank, 

 and Frederick Edwards, in London ; of the Museum of Natural History, and of 

 MM. d'Archiac, Michelin, and Milne Edwards, in Paris ; M. Nyst, at Louvain ; M. de 

 Koninck, at Liege, &c. 



Genus Flabellum (p. xviii). 

 1. Flabellum Woodii. Tab. I, figs. 2, 2 a, 2 b. 



Fungia semilunata, 1 Searles Wood, Ann. and Mag of Nat. Hist., vol. xiii, p. 12, 1844. 

 Flabellum Woodii, Milne Edwards and J. Haime, Monogr. des Turbinolides, Ann. des Sc. 

 Nat., 3 me serie, vol. ix, p. 267, 1848. 



Corallum simple, erect, rather short, much compressed, especially towards its base, 

 cuneiform, subdeltoid, with a peduncle short and rather thick, and lateral edges straight, 

 and diverging at an angle of rather less than 90°. All the costa, even the lateral ones, 

 simple, flat, equal, indistinct, and crossed by scarcely developed rugae and slight folds 

 of the epitheca, which is very thin. The surface of the wall is also marked by small longi- 

 tudinal sulci, corresponding to the outer edge of the septa ; those referable to the small 

 septa but slightly marked. 



Calice having the form of a very long ellipse, and rather arched. In one specimen 

 the proportion of its two axes was as 100 : 280, and in another as 100 : 300; the ex- 

 tremities of the ellipse corresponding to the great axis are obtuse, and on a level rather 

 lower than that of the small axis. The fossula is long, narrow, and deep. 



The columella represented only by few large granule adhering to the inner edge of 

 the septa, and assuming the form of short, thick trabiculse. 



The septa constitute five complete cycla, very well developed, and a sixth cyclum 

 incomplete, more or less rudimentary in some parts, but most apparent in the systems 

 situated near the long axis of the calice. The septa of the first three cycla are nearly 

 of the same size, and the septal apparatus is therefore divided into twenty-four groups or 

 apparent systems^ containing each seven septa, or only five, as is often the case when those 

 of the sixth cyclum are missing in half of these groups. In general, these minor septa are 

 most developed in the half of the lateral groups adjoining the extremities of the long axis 

 of the calice, and at the same time the septa of the fourth cyclum enlarge in these groups 

 so as to resemble the neighbouring ones of superior orders, and produce an appearance of 

 there being twenty-six or twenty-eight systems ; but in these lateral groups the number of 

 septal elements never exceeds three. 



The septa are straight, thin, closely set, and do not rise quite so high as the mural 



1 The Fungia semilunata of Lamarck, to which this fossil was referred by Mr. Searles Wood, belongs to 

 the genus Biploctenium of Goldfuss ; hence the necessity of giving a new name to the above-mentioned 

 species. (See our Monograph of Astreidse, Ann. des Sc. Nat., 3 me serie, vol. x, p. 248.) 



