AUSTRALIAN PORITES. 147 
granules joined together by narrow waists, which show the typical skeleton of Porites. The 
ring of septal granules is separated from the wall by a narrow inconspicuous circular furrow. 
The pali are slightly larger, but are not raised. The usual formula consists of the five principals, 
but occasionally that of the dorsal directive is pushed in far enough to make the ring six 
instead of five. The central tubercle is large, often flattened, and rises to very near the surface. 
Round the base of the stock all these granules are larger, and become so compact that the 
surface is smooth and velvety and the calicles disappear from the unaided vision, and are 
only distinguishable under a lens by the arrangements of the granules. 
The section shows a strong development of the trabeculae, but with some irregularity in 
their distances apart, some of the intervening pores being very small, others very large. 
The colour of the unbleached coral is dark reddish-brown. 
This coral has exactly the structure of calicles seen in many another branching Porites. 
See Table III. Their growth-forms are all different, and the localities are different. What 
their genetic inter-relationships are have to be discovered. As already stated, we do not yet 
know whether the calicle structure is a function of the growth-form, or vice versd. I am 
convinced of the fact that, in spite of the variations of the growth-form, even among specimens 
obviously of the same kind and gathered side by side, the growth-form as a taxonomic 
character cannot be neglected. The analysis of many specimens shows clearly that there is a 
tendency to produce and repeat peculiarities of form, not only all over the same stock, however 
large, but in all obviously related specimens. 
a. Zool. Dept. 92. 12. 1. 353. 
140. Porites North Australia (g8. (P. Australie Borealis tertia.) 
(Pl. XXII. fig. 4; Pl. XX XV. fig. 14.) 
[Franklin Shoal,* Arafura Sea, 9 fathoms ; British Museum. | 
Description.—The corallum throws up here and there from a large encrusting base, with 
thin edges (under 1 mm.) and rough warty surface, shapeless, angular and rudely branching 
processes, some reaching 4-5 cm. high. 
The calicles are minute (under 1 mm.), very ill-defined, and visible mainly as faint rings 
of pali round a small fossa, quite superficial, and unevenly distributed. The walls are thick, 
usually flat, covered by a mosaic of frosted granules, not echinulate nor bushy ; over small 
areas the walls are rounded and raise the surface into warty prominences. The septa are not 
visible. There is an irregular ring of wall granules. The pali, separated by a circular trough 
from the wall granules, form neat circular rings flush with the surface; they are large, triangular 
rather than V-shaped, and have the same character as those of the wall and surface; there 
are from six to eight, the five principals being large. The minute central fossa is usually 
closed by a tubercle at a slightly lower level than the wall. 
* 9° 529’ S,, 129° 19' E. 
U 2 
