GARDINER—MADREPORARIAN CORALS. 285 
1 2 3. 1 5 | 
= | 20 ef | 
TLengthh $3 naryeehite alsrate 73 15:5 21 28 25 | 
Breadth jen sete cctastcitees ste a7 6:3 it 8:5 (a2 | 
Heightypeaace nae ct ciecserne 1:9 2°8 4 6°7 | 9 
Depth of aboral side ...... 3 8 1-6 3:2 | 4:5 
| 
Localities. Nos. 1-4, reefs off Singapore, stated to be “very common in all parts,” 
collected by the late Mr. F. P. Bedford; and No. 5, reefs off Sawakin, Red Sea, collected 
by Mr. C. Crossland. The species is recorded as having been previously obtained from 
Ceylon and the East Indies as well as the Red Sea, Zanzibar, Fiji, and Tahiti, but I think 
the last three localities are not fully authenticated. 
The first four specimens above represent four stages in the growth of the species. 
No. 1 is a small dise which has only receutly broken off its stock, its sear 11°5 by 8 mm. 
not having as yet been overgrown by the polyp-tissues; the costal spines radiate from 
the scar. The axial furrow is broken by the fusion across of septa in four places forming 
five secondary calicular centres ; otherwise it is about 1-3 mm. across and closed in below 
by finely packed trabeculze from the septal edges. As yet there is only the commence- 
ment of five subsidiary centres on the sides of the disc. (Plate 38. figs. 20, 21.) 
No. 2 still shows its scar, but the radiating arrangement of the costal spines is lost for 
about 3 cm. at either end of the scar and for 1°5 cm. on either side. The axial furrow 
is broken across in fourteen places, and is still relatively open, showing the columellar 
trabecule. Subsidiary side calicular centres have begun to form fairly freely at varying 
distances not less than 15 cm. from the axial furrow. (Plate 39. figs. 24, 25.) 
No. 3 is simply the last enlarged, with the scar still distinct and the axial furrow 
rather narrower, but yet having the columellar trabeculee quite visible. Its oral surface, 
which has evidently been damaged, has in one spot commenced to grow out a fresh 
disc, best seen in the figure; it shows a central furrow and has turned round through a 
right angle so as to lie parallel to the parent disc. (Plate 38. fig. 23.) 
While Nos. 1-3 are rather flat and pointed at either end where the axial furrow passes 
out, No. 4. is strongly arched and rounded at its ends, the axial furrow stopping short 
where the dise begins to bend downwards. The costal spines nowhere form lines for 
more than 1°5 cm. inwards from the edge of the disc, and the area inside is very rough, 
rising into numerous, small, spine-covered mounds. The septa in the axial furrow 
approach so closely that no columella can be seen from the surface. The whole oral 
side is very uneven, many of the septa being thickened and even fused together in 
places, these septa having quite ragged edges. I should judge the specimen to he one 
which has lived in peculiarly unfavourable conditions, probably on a sandy bottom, as it 
is much arched, and where silt is depositing, particles of sand probably having produced 
its uneven surface. 
