INDIAN OCEAN PORITES. 203 
which are large, and all the elements are smooth and thin. Down the sides the elements 
thicken, and become rows of sharply defined granules, the walls usually consisting of a single 
row, with all stages in the appearance of a second by the formation of an inner synapticular 
wall. The septa are clear, sharp, thin, and lamellate, but in the lateral calicles they thicken, 
and both septal granules and pali appear, the latter usually in the complete formula of eight. 
A large, irregularly reticular columellar tangle can usually be seen high up in the fossa, 
and from it a small granular tubercle arises. The interseptal loculi are very large, round, 
and open in the uppermost calicles, while their star-like radiation in the lateral calicles is 
visible to the naked eye. 
The colour is brown. 
This coral is quite different in its calicle formation from any of those hitherto described. 
It is impossible, in the present state of our knowledge, to say whether the differences are in 
any way due to the modifications which the colony had to undergo in adapting itself to such 
a small foothold as a thin branch of a Madrepora. 
On the under surface there are calicles which may have been alive when the stock was 
found, but which did not belong to the last growth-period, the edges of which can be traced. 
These appear to have grown in this same unfavourable ventral position, for they have very 
thick, solid walls, composed of a compact mass of large granules, while large septal granules, 
pali, and tubercle fill up the calicle. 
There is one other quite free stock in the series (see No. 9). Almost all of them without 
exception were in reality free, but rested on broad flat bases. This and No. 9 were apparently 
rolling, unless the remains of the Madrepora hindered this one, and this is probable, for there 
are signs of the formation of a thick, cushion-shaped rim for the production of a resting base. 
a. Zool, Dept. 1904. 10. 17. 49. 
Five of the remaining specimens may, with some certainty, be placed together. Their 
growth-forms require describing, but the calicles are all variations on one type, and most of 
the variations can be found on each specimen. 
204. Porites Ceylon (928, (P. Ceylonica octava.) (Pl. XXX. fig. 9.) 
[Ramesvaram, coll. E. Thurston; British Museum. | 
Description—The corallum stands upon some small object, round which its own base 
spreads freely all round with a very thick, chalky epitheca. Above the cushion-shaped edge 
the stock rises into great masses of various shapes, but all showing a tendency to column 
formation, which may be so compact that the whole is a cylindrical mass, with vertical 
flutings round the sides, the tips of the columns showing more or less separate only on the top. 
The calicles are very variable in size, from 1*2 mm. down to the minutest buds; they 
are shallow, and, according to the character of the wall, either circular or very angular. The 
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