PORITES. 25 
of these vertical bars usually stand up above the surface as granules. In addition to the central 
tubercle, usually two granules appear on each septum, and one on the wall, and perhaps others 
between the wall granules of adjoining calicles. Two pairs of adjacent septa always fuse on 
each side of the directive plane, and the surface granules at their fusions form four usually 
conspicuous pali. Granules rising from other septa may join the ring of which these four pali 
are the principal members. 
VII. DISTRIBUTION IN TIME AND SPACE OF THE INDO-PACIFIC FORMS. 
The Table II. of the analytical section, shows at a glance the distribution, not of the 
forms of Porites, but of those forms alone which I have been able to examine. This distribution, 
then, is quite untrustworthy as representing the real facts. Certain regions have been examined 
and collections made therefrom ; other regions wait. I have, for instance, seen no specimen at 
all from the Mergui Archipelago, yet Porites is said to be very abundant there; from the 
Maldives also I have been able to study but a very few specimens, although since the text was 
written I have seen a large collection from that locality made by Mr. Stanley Gardiner. 
It is probable that Porites occurs on every reef: it may be, indeed, that it is an almost 
essential element, in that its density, noted above, makes it an important factor in 
strengthening the outer edges of the reef against the surf. Be this as it may, it is very widely 
distributed through tropical seas, and the forms here recorded are but a handful of samples 
rather than a truly representative collection, 
I have extended the Indo-Pacific area in the South-west to the Cape of Good Hope, where 
a form occurs, probably on the shores of False Bay, in which the water is several degrees 
warmer than it is in the Atlantic. 
The fossil forms of these Indo-Pacific regions are an almost unworked field. We shall 
find them slightly better represented in the Mediterranean and West Indian areas, probably 
not because they are more abundant, but simply because those regions have received more 
attention from specialists in fossil corals. 
VII. ON THE METHOD HERE ADOPTED OF PRESENTING THE FACTS. 
This volume is written on exactly the same lines as Vol. IV. It is an attempt to present 
the facts by word and figure, without any assumption of knowledge which we do not possess. 
No published objections have come to my notice which might have called for reply or comment. 
One apparent deficiency has, however, been pointed out to me verbally, It has been 
suggested that, for fossil forms, an extra term is needed to designate the horizon. With regard 
to this, I would point out that the geographical designation is not a description, but only a 
formula of reference. The addition of the horizon will only become necessary in certain 
EK 
