CORALS OF THE CRAG. 7 



epitheca ; their upper edge is slightly sinuous, and their surface covered with projecting 

 granular of various sizes, disposed rather irregularly in rows nearly parallel to the upper 

 edge. These granulse are much larger along the inner and inferior part of the edge of 

 the septa of the superior orders, where they assume the appearance of alternate trabiculae 

 or spines. It is also to be noted that the principal septa are slightly emarginated near 

 the border of the calice, and that their free edge is thin and arched above, thick, 

 subflexuous, and obliquely truncate towards the columella. A horizontal section of the 

 corallum, made a little below the edge of the calice, shows the thickness of the walls, 

 and of the inner part of the large septa ; it also renders evident the bifoliate structure of 

 these septa. Height twelve lines ; long axis of the calice from twelve to sixteen lines ; 

 the short axis from four to six lines. 



The genus Flabellum contains a great number of species, and has been subdivided 

 into three sections, according to the state of the basis of the corallum, which is sometimes 

 pedicellate or truncate, and in others widely adherent. The Flabellum Woodii is easily 

 distinguished from the fixed Flabellum and the truncated Flabellum, by the permanence of its 

 narrow peduncle, and differs from most of the pedicellated Flabella by its simple non- 

 cristate, non-spinous costse. Seven species, F. Gallapagense, F. Michelinii, F. Thouarsii, 

 F. cvMeatum, F. subturbinatum, F. majus, and F. Sine use, have the same character ; but 

 F. subturbinatum and F. Michelinii are recognisable by their horizontal calice and their 

 lateral costse, almost vertical. F. Gallapagense also resembles F. Woodii by the rudimentary 

 state of its columella, but is of a more elongated fonn, and is much less compressed laterally. 

 F. cuneatum and F. majus are still nearer allied to F. Woodii, their characters, however, 

 are not yet completely known ; but the first of these fossil species has the septa much 

 thicker than in the above-described Coral, and Flabellum majus is remarkable by its great 

 size, its highly-compressed calice, and the peculiar structure of its principal septa. 1 



The Flabellum Woodii has been found in the Coralline Crag at Iken, and appears to be 

 very rare ; for in 1844, when Mr. Searles Wood published his ' Catalogue of the Zoophytes 

 of the Crag,' only two specimens, one belonging to Mr. Bunbury, and the other to Mr. W. 

 Colchester, were known, and we believe that since that time only two more specimens, 

 now in the possession of Mr. Searles Wood, have been found. Those figured and 

 described in this Monograph were communicated to us by Mr. Searles Wood. 



' See our Monograph of Turbinolidse, loc. cit., p. 2rjM. 



