POLYNESIAN PORITES. 73 
49. Porites Ellice Islands q7l0. (P. Elliciana decima.) (Pl. VI. figs. 7, 8; 
TAL OY wks IB) 
[Funafuti (lagoon), coll. J. S. Gardiner; British Museum. | 
Syn. Porites arenosa (partim) Gardiner (non Esper), Proc. Zool. Soc. (1898) p. 272. 
Porites parvistellata Gardiner (non Quelch), ibid. 
Deseription.—The corallum rises as a smooth-topped rounded mass, with closely adherent 
edges; the sides of the stock are either steep or bending outwards to encrust masses of dead 
coral all around. 
The calicles vary greatly in size, the larger being 1:5 mm. in diameter; numbers of small 
buds appear, like minute solid rings, raised up on the angles between the calicles. The wall- 
ridge is everywhere conspicuous, and is mostly a smooth solid ridge without pores, and with 
but slight traces of its composition out of trabecule, although patches here and there show both 
these characters; in parts the wall may even be a reticulum. In association with this solid 
ridge is the tendency seen over the greater part of the upper surface to form a smooth con- 
tinuous shelf round the calicle below the edge of the wall; from the edge of this shelf the septa 
; project. That this shelf is formed by the bases of the septa is clearly shown, for in those cases 
in which one or two septa project directly from the wall-ridge above the shelf, their basal 
sections are usually broad flakes. The septa when springing from the edge of the shelf are 
short and often rise almost at once as frosted granules. There is consequently a very large 
number of these granules running round the fossa, recalling the condition seen in P. Ellice 
Islands 5. The fossa is open and deep, a columellar tubercle sometimes appearing deep down. 
There are three specimens, one a large irregular mass, one of Mr. Gardiner’s P. arenosa, 
and two small stocks, the larger of which Mr. Gardiner suggested might be related to the 
P. parvistellata of Quelch (see, however, P. New Hebrides 1, p. 81). In this last named 
specimen there are two remarkable variations on the type of calicle above described. On one 
side of the stock (Pl. VI. fig. 8*) the synapticular shelf is only irregularly developed, and 
then it is seldom complete, but perforated; the calicles are very deep, both fossa and inter- 
septal loculi; the septa fuse sufficiently to send up the four principal pali as stout conspicuous 
rods nearly as high as the wall. On the opposite side of the stock the wall-ridge is frosted, 
and is sometimes thick and with a solid shelf (Pl. VI. fig. 7 *), at others almost a reticulum ; 
the septa slope down into the fossa, frosted, thick, and without any developed ring of pali. 
The fossa is funnel-shaped and not deep. 
There can again be no doubt that these are all related together, and to the last forms. 
But how are we to deal with the astonishing differences if we simply group them under one 
name with a common description ? 
a. Zool. Dept. 1905. 1. 19. 20. 
b. Zool. Dept. 1904. 10. 17. 30. 
C. Zool. Dept. 1905. 1. 19. 21. 
* The collotypes do not sufficiently bring out the distinction between the wall-ridge and the shelf. 
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