Protandry and Senescence of Corals. 
469 
adjacent sides. The Minikoi specimens correspond to the last 
state found in Flabellum , and it is interesting to remark that the 
two colonies examined were the only living ones found in this 
locality, although dead corolla were very constantly turned up. 
One part of the reef at Rotuna, some hundreds of square 
yards in extent, was nearly completely overgrown by a coral, 
which I identified as Madrepora pulcra Brook, var. alveolata 
Brook 1 . This is one of the staghorn-growing species of the genus 
with widely separated branches, and was not found save in this 
single area. Most of the stems were dead at the base, the coralla 
in some parts of the area having no living polyps at all. In three 
living twigs, which I examined, all the polyps of every part were 
female. The ova were very far from regular, some of the polyps 
having on their mesenteries isolated ova, others no ova at all, 
though they had evidently recently possessed them. All the 
branches over the whole area were evidently dying. My exami- 
nation, which was made in 1898, was undertaken to ascertain the 
cause, but was without result. No trace of silting up by mud 
was found, nor was there marked shrinkage and decay such as 
results from drying up owing to undue exposure to the sun and 
air. The endoderm was everywhere devoid of food granules, but 
except in its staining properties appeared healthy. The con- 
dition again is only paralleled by that of the largest Flabellum , 
suggesting that the same operative cause may have acted in 
both cases. 
Death of the corals on reefs is common, and has been observed 
by most workers thereon. In some cases it may have been due 
to exposure, in others to silting up or even too high a tempera- 
ture, but in such not one nor two species of corals nor even 
genera would be affected, but all coral growth on the area. In 
addition there is much death, which cannot properly be assigned 
to environmental causes, where single colonies die or a number 
of colonies of a single species in a particular area. Separate 
dead colonies, enormous masses perhaps, are often found where 
neighbouring colonies of the same species, both large and small, 
are flourishing. 
A different case — here and there observed in the Maldives — 
would be that where a species or genus of corals was absent in 
the living condition from one reef, while on the next with 
apparently absolutely similar conditions it was perchance growing 
luxuriantly. Living Coeloria daedalea was absent from the west 
or seaward reef of Addu Atoll off Maradu, while Leptoria tenuis 
was extremely common, forming large colonies. The reverse in 
these two species was the case on the seaward reef off Midu to 
the north-east of the same atoll. Elsewhere in the Maidive 
1 Pruc. Zool. Soc., 1898, p. 259. 
33—2 
