42 MADREPORARIA. 
curve. The specimens are perhaps distorted by Balanids. The basal stems are about 
1°5 cm. thick, and the living layer 6 cm. deep, with a lower edge tending to creep. 
The calicles are almost superficial, about 1°25 mm. in diameter ; the raised wall-ridge, con- 
sisting of single irregular rows of small straggling granules, traces a polygonal pattern over the 
whole surface, except in the forks. The walls seem to be formed out of continuous flakes, 
which are thick, slightly wavy, and with tilted ends; the pores in the flakes are few and small, 
and their edges, where they border the calicles, are deeply incised to produce the irregular septal 
tongues which may project from different levels of the wall. These septal tongues are broad, 
with rough edges, and there is only a trace of the typical radial symmetry in the incisions, 
which themselves represent the interseptal loculi. There is a large and conspicuous ring of 
pali, apparently in formula B, fig. 3. From the shallow fossa a small tubercle can be seen rising 
from the flakes which fill it up. The transverse section shows the immense development of 
the horizontal elements at the expense of the trabecule. 
There are three specimens: (a) a small tuft showing the method of growth; (6) a single 
detached stem which fits on to a; and (c) a portion of the dead previous growth, one tip of 
which has a small plate-like colony, 2 cm. in diameter, growing out horizontally from it, and 
with edges slightly turned up. The character of its calicles and the resemblance between its 
section and the cross sections of the dead stems on which (and, presumably, from which) it grows, 
show that this is a small explanate stock of this same Porites. 
Whether this dise is merely an accidental shape assumed by the creeping edge, or a new 
colony starting as a basal disc from the centre of which a new branching stock would have 
arisen, we have no means of deciding. If the latter, it is of great interest, for it is rare to find 
the earliest growth stage of branching forms. 
Only one Porites having the skeleton built up mainly of the horizontal elements has 
hitherto been recorded, namely, the Singapore form (No. 7), Briiggemann’s “ P. sacharata” ; 
several, however, are now known. In this, and in the Singapore form, we have two calicles 
of essentially the same type of structure, but differing considerably in detail: in P. Singapore 7 
the flakes are larger and with fewer granules, and, further, the growth-form is quite different. 
No object that I can see is gained by uniting into one species all forms which show the same 
type of calicles; we should only be assuming knowledge which we do not possess. It is 
more philosophical to record the facts in tables, as is here done. The distribution of this type 
of calicle associated with other growth-forms will be given in the Analytical Tables at the end 
of this Volume. 
a, A small stock. Zool. Dept. 1904. 10, 17. 13. 
b. A single stem detached from a. Zool. Dept. 1904. 10. 17, 14. 
c, A dead fragment with small disc (? a new = 
colony in its earliest stages) attached. Zo De Ee 
