GARDINER—MADREPORARIAN CORALS. 283 
thinner, and more finely toothed septa, while its costxe are much more definitely 
radiating with smaller spines. Its subsidiary calicular centres on the sides of the disc 
are even more indistinct than in H. limaz, in which character both species markedly 
differ from H. tnterrupta and H. crassa. At first I was inclined to regard the species 
as almost a delicate form of HH. limax due to environment, but the discovery in 
Mr. Crossland’s collection of a specimen of that species from the same reefs * and the 
examination of 12 specimens of ZH. limax in the British Museum have caused me to 
modify this opinion and to deem them two distinct species. In the 18 specimens of 
H. limax which I have examined I have found no case of the breaking of the dise and 
its regeneration comparable to that described in three of the specimens of H. foliosa 
mentioned below. 
Locality. Red Sea, from reefs off Sawakin. Previously collected only from the reefs 
of East Africa and the Red Sea. 
The specimens in the collection require individual mention. The smallest is 24 em. 
long by 5°5-6:5 em. broad by upwards of 4 cm. high in the centre. Its scar of 
detachment is still recognisable, being about 5 mm. across. A central furrow extends 
from end to end of the disc, about 1 mm. across, and filled in below by a maze of fine 
columellar trabecule. In its whole length it is broken across in twenty-three places by 
pairs of septa of opposite sides fusing, but the septa do not in any way bend round 
towards individual calicular centres in the axial line. The septal sides are ridged, 
corresponding to the very fine angular teeth, of which there are about 20 in 10 mm. 
The coste are remarkably fine, covered with very small, low, blunt, granular spines, at 
least 20 in 10 mm.; they radiate out from a central, oval-shaped, imperforate area 
which is about 4 by 15 cm. (Plate 36. figs. 14, 15.) 
The second specimen is a complete disc similar to the last, about 43 cm. long by 
16 cm. broad by 10 em. high. It agrees closely with Klunzinger’s figure, and differs 
from the last only in showing characters due to greater age and size, such as thicker 
and higher septa, slightly coarser teeth, narrow axial furrow stopping short a few 
centimetres from the ends of the corallum, coarser spines to the coste, &c. The 
central imperforate area is scarcely larger than in the last specimen and the costal 
spines radiate from it quite distinctly. 
The third specimen is 28 cm. long by 22 cm. broad and 8 em. high. It has had its 
origin from a fragment out of the side of a corallum which split down along its axial 
furrow, subsequently breaking up transversely, 7.e. parallel to the direction of the septa. 
The original piece was about 11 by 11 cm., and considerable irregularity is shown 
where regeneration has gone on from the line of the original axial furrow, though there 
is no attempt to re-form it. Re-growth has also taken place from the other sides, but 
the whole specimen has a most irregular appearance, as the septa and costze in the new 
portions run out at right angles to the growing-out edges quite independently of the 
direction of the septa and costze of the original fragment, indeed running out in places 
at right angles to them. 
* See under H. lima below. 
39* 
