129 



The species of Edwards and Haime differ from one another 

 mainly in the shape of the calicle, presence or absence of 

 spines near scar of corallite and systems of septa. The first 

 of these varies greatly in my specimens. The compression 

 in some is very slight, the angle made by the two flattened 

 sides with one another being from 15'^ to 60° or 70''. Taking 

 the long axis as 100, the short axis varies in Xo. 5 from 44 to 

 66, in No. 4 from 37 to 71, and in No. 3 from 43 to 83. 



The wings are at first hollow, but owing to deposition of 

 corallum inside become more or less solid. They are quite 

 distinct in 80 per cent, of Nos. 4 and 5. Sometimes they 

 continue up evenly on both sides, but generally there are 

 small wings only at the end of the accretion lines, which 

 probably show periods of rest ; the two sides are not usually 

 by any means symmetrical. In the larger specimens they 

 are not so clear, but still traces are commonly present near 

 the basal scar. With growth, in some cases, there seems to 

 have been a certain amount of solution of the epitheca outside 

 and deposition of corallum within. The wings might by this 

 means become blunt spines. This may be partially the case 

 in Nos. I, 2 and 3. Of these, two have clearly wings, four 

 are rounded at their ends, and ten have at least a pair of 

 spines near their basal scars. Five smaller specimens of o.her 

 dredgings have also paired spines, not wings. Three of these 

 are very small, and without the specimens of Nos. i, 2 and 3 

 it would naturally have been stated, when the corallum was 

 thought to be of endodermic origin, that spines are charac- 

 teristic of young individuals. 



The septa vary with age up to 168, the maximum found. 

 No less than 105 out of it 8 specimens recorded in the table 

 had 20 fusing by trabeculae, thus corresponding to F. irregulare 

 Semper. This, however, appears to be only a stage of 

 growth as any of the septa of cycle III. may be among the 

 four, which fail to fuse by their trabeculae. The two sides of 

 the calicle do not necessarily correspond, and every possible 

 variation is found, in one with 24 large septa, the number 

 being made up by the enlargement of 2 septa of cycle IV. 

 In the majority of cases with 20 large septa it is the two 

 central side pairs of cycle III. that fail to fuse. 



In some cases the horizontal upper edges of the septa rise 

 above the upper edge of the epitheca, while usually they lie 

 in the same plane. In No, i they rise above it, but in some 

 specimens ol No. 3 lie about 1-5 mm. below, the appearance 

 being as if their edges had been shaved down near the 

 borders of the calicle. 



An examination of the type specimen of F. traiisversale 

 Moseley showed that it belonged to the same species, being 

 merely a single corallite that had not lost its stalk. F. thoiiarsi 



