AUSTRALIAN PORITES. 153 
This is not the only case known in which the apparent explanate growth is not the natural 
growth. An exactly similar phenomenon in the case of a Goniopora from the same district 
will be found described in a supplement given in Part II. of this Volume. See also the 
remarks there made as to the bearing of this upon the species question. 
The very broad flakes composing the walls of this coral are not common, at least among 
the Indo-Pacific Porites. 
a. Zool. Dept. 92. 1. 16. 37. 
147. Porites North-West Australia (g2. (P. Australie Occidentalis secunda.) 
(Pl XXIII. fig. 2; Pl. XXV. fig. 2.) 
[Holothuria Bank; British Museum. 
Description —The corallum rises into irregular clumps of short round lobes or knobs, 
standing out in all directions. The thin edges are pendent or turned outwards. 
The calicles are small, 1 mm. in diameter, sub-circular, slightly depressed, but not con- 
spicuous. The walls are either simple and zigzag, with top edge seldom seen complete, but 
rising into rods ending in frosted swellings, or (on steep sides) an open flaky reticulum with 
round pores and the ends running out into minute fan-shaped knobs with echinulate distal edges, 
The septa are rods swollen and nodulated, and sending up echinulate granules. The five stout 
principal pali, often with a minute (dorsal) directive palus, rise a short way above the loose 
septa. The fossa is here and there quite open, but usually closed by a few distinct stout strands 
of a loose columellar tangle, from which arises a small central tubercle with frosted tip. The 
interseptal loculi are very large, and open very widely into the fossa. 
The section shows very stout, rather wavy trabecule not very closely arranged, with, at 
least in the horizontal explanate portions, very feeble development of the horizontal elements. 
These would probably be more developed on the steep sides. 
The unbleached coral is a pale yellowish-brown or buff colour. 
Except that there is not the same pronounced explanate base, this coral reminds one in 
growth-form and in the character of the calicles of P. Ellice Islands 3 and P. Fiji Islands 24. 
But none of them are really alike. It would appear as if a general openness or looseness of 
calicle skeleton accompanies this kind of growth-form. 
a. Zool, Dept. 92. 1. 16. 47. 
148. Porites North-West Australia @)3. (P. Australie Occidentalis tertia.) 
(Pl. XXIII. figs. 3, 4.) 
|Baudin Island reef; British Museum. ] 
Description.—The corallum is a smooth, rounded or oval nodule, with flattened top. The 
creeping edges bend a short way under, 
x 
