POLYNESIAN PORITES. 105 
The calicles, opening in the stroma on the top of the ridges here, have a less pronounced 
columellar tangle than have those opening on the flat tops of the stems in the P. Sandwich 
Islands 8. 
a. Zool. Dept. 86. 12. 9. 311. 
88. Porites Sandwich Islands (8, (P. Hawaiensis octava.) (PI. X. fig. 2.) 
[Honolulu, 1-2 fathoms, coll. H.M.S. ‘Challenger’; British Museum.] 
Syn. Porites tenwis (partim) Quelch (non Verrill), Chall. Rep. xvi. (1886), p. 184. 
Description.—The corallum closely encrusts stones with a layer about 5 mm. thick, 
Successive layers of the same thickness cover one another, and can be scaled off. Edges closely 
adherent. 
The calicles are superficial, polygonal, and 1°5 mm. across if taken from median ridge 
to median ridge, but round and 1:25 mm. if the circumference of the interseptal loculi is the 
periphery of the calicle. The wall has a low frosted or finely toothed median ridge, and a 
flaky shelf on each side of it. Here and there the shelf is very porous, and the wall appears 
to be reticular. The rows of the pores are sometimes nearly regular enough to suggest the 
trimurate condition (see Introduction, p. 16), The septa are symmetrical, but slightly 
roughened, and septal granules appear at the edges of the flaky shelf. The interseptal 
loculi are conspicuous and open. The pali form a neat ring, and are frequently complete. 
The columellar tubercle is granular and smaller than the principal pali and slightly below 
their level. Itself seldom flattened, it may frequently be seen to rise from a directive lamella 
running across the whole calicle. 
This coral from Honolulu is represented by a spirit specimen and a cleaned fragment 
which has been scaled off the living layer. The growth-form is peculiar, and deserves 
separate description. From the other Honolulan Porites it differs not only in method of growth, 
but in its calicle formation. There are no high membranous walls, and the pali are con- 
spicuous. But on the other hand it may be noted that the thin skeletal elements, the open 
interseptal loculi, and their symmetrical septal formula, is common to all these Honolulan 
corals. 
The absence of high walls in this specimen may be an adaptation to a detached life (cf. 
P. Ceylon 9). As the growth is all on one side, however, the stock, when collected, appears to 
have been stationary. 
Mr. Quelch identified this form with P. tenuis Verrill. But P. tenuis was glomerate, 
whereas this, forming a rounded mass from encrusting a round stone, is really encrusting. 
The fact that layer covers layer with discontinuous growths separates this from true glomerate 
forms, in which the corallum thickens continuously. The rest of Dr. Verrill’s description is so 
general that it might apply to almost any member of the genus. 
a. In spirit (with a fragment freed from the aa Zool. Dept. 91. 2. 20. 2. 
parts in order to show the calicular skeleton). 
P 
