ANALYSIS AND DISTRIBUTION OF TYPES OF CALICLES. 285 
in the latter only one—and in P. Great Barrier Reef 5 even that remaining ring is greatly 
diminished. Looking at the sizes of the sub-divisions, it is interesting to note that the largest 
number of forms occurs in the last division but one (0, iv.), in which the wall and septal trabeculz 
unite to form the dividing walls between adjacent calicles, leaving only 1 ring of trabecule in the 
intra-calicular skeleton. The tendency of the genus is clearly then towards minute calicles. 
Tt is also noteworthy that this minuteness of calicle is attained within the genus in two 
ways: (1) as above described, by what looks like rapid budding and consequent crowding, so 
that the number of rings of trabecule to each calicle is gradually cut down to one, viz., the pali; 
and (2) as seen in the ccenenchymatous forms, where the walls are greatly thickened, and 
where perhaps we may say that, as in Montipora, which is the smallest calicled Madreporid, 
the calicles have suffered in order that the walls might be especially developed. 
D. Those Porites in which the trabecular elements are no longer recognisable, either 
(a) because the whole skeleton is melted down into a fluent network, or (>) because the 
horizontal elements are developed at the expense of the trabecular. 
a. This applies to all tops of forms which show the expanding sheaf method of growth ; 
also to— 
P. Timor-laut 1. On all the top surface, perhaps indicating the method of 
growth just mentioned (see B, J, ii.). 
P. Ceylon 1 and 3 A fluent network, explained perhaps by P. Ceylon 2 
(see C, 0, 1.). 
P. Ceylon 6. Skeleton consists of vertical lamellze, perhaps also indicative of 
the expanding sheaf method of growth. 
P. Ceylon 11. Tt is doubtful whether this has not had the onginal surface worn 
down. (The fact that the skeletal elements can be seen to be hollowed 
out by a boring alga confirms this suggestion.) 
P. Red Sea 5. (See the British Museum specimen.) 
b. The horizontal elements developed at the expense of the trabecular, the tips of which 
are usually just traceable as minute granules. (The opposite extreme to this is 
P. Great Barrier Reef 5, in which the trabecule run to an extreme in length and 
size, though their numbers are reduced to a minimum.) 
P. Banda Sea 2 
P. Philippines 6 
P. China Sea 4 
P. Java Sea 2 
P. Singapore 7 
- See descriptions in text. 
E. Branching non-ccenenchymatous forms, the tips of which mostly consist of a 
streaming axial reticulum, show the following variations in their calicles. 
a, The walls rise in the usual manner, showing no special development of either the 
trabecular or horizontal layers. 
b. The trabecular layers are especially developed, the tips of the trabecule making a 
smooth mosaic over the surface. 
c, The horizontal layers are most developed, so that the surface consists of flat flakes, with 
the trabecule as scattered granules. 
