86 MADREPORARIA., 
wavy or zigzag threads (or porous plates) which do not rise above the surface. The narrow 
lamellate septa project sometimes quite from the margin, sometimes just below it, often angularly 
bent and with traces of an inner synapticular wall uniting them together, but they always rise 
up to the level of the wall. The pali are long thin rods tipped with minute pointed branches ; 
one or two may be connected with the septa near the margin, but mostly the connection is 
some way down in the calicle. Formula D, fig. 3 (see Introduction, p. 19) seems most common. 
The central tubercle may be a thin flake. Between these thin membranous and filamentous 
elements of the skeleton one can see down (that is, everywhere it has been cleaned) into the 
depths of the coral, there being no conspicuous columellar tangle filling up the fossa. 
There is one large, smooth, rounded mass 12-13 cm. high and 15 in longest diameter. 
The mass growing on a narrow base appears to have rolled on to its side, as shown in 
Pl. XIII. fig. 26. 
This specimen was labelled by Mr. Ridley Porites tenwis (see P. China Sea 1). But 
Dr. Verrill’s original description of P. tenwis is too general and might apply to almost any 
glomerate Porites. The localities, also, are so far apart that the chances of the two forms being 
specifically identical are very small indeed, The uniformity in thickness of the thin mem- 
branous wall- and septal-edges, the character of the pali, coupled with the small sizes of the 
calicles, the scantiness of the columellar tangle (so that one can see deep down the open inter- 
septal loculi, which do not seem to close up by any apparent thickening of the skeletal elements) 
are the chief features of this coral. The surface is very smooth to the touch, and the dried 
coral is a dull fawn colour. 
a. Zool. Dept. 84. 12. 11. 11. 
64. Porites Solomon Islands (4q)6§. (P. Salomonis sexta.) (Pl. VIIL. figs. 5, 6.) 
[Shortland Island, coll. Dr. Guppy ; British Museum.] 
Deseription.—The corallum forms great solid masses, which envelop the tips of stout branch- 
ing corals. Its surface, otherwise smooth, is much broken up into a confused system of ridges 
with slight keels along their top, and sharp, narrow, intervening valleys. The edge of the 
living layer is closely adherent, and creeps under into crevices and holes. 
The calicles are shallow, very angular, very variable in size, up to 1°25 mm. The walls 
are low and straight, composed of either threads or rows of granules beset with blunt points ; 
seen sideways, they are very porous and fragile, the edge granules being the flattened tips of 
trabecule. Within the wall, or some way below its edges, there are frequent traces of an 
inner synapticular wall, which is here symmetrical and regular, there melted down with the 
wall into a fragile flaky reticulum. The septa are lamellate, porous, delicate, crisp, slightly 
bent, and beset with blunt points and angles. Owing to the irregularity of the inner synap- 
ticular wall, the septa often seem to fork near the wall, but the formula is that of Porites. The 
pali are lamellate plates, rising together like a conspicuous boss from the centre of the calicle 
nearly as high as the walls, the four principals often V-shaped. The tips are very slightly 
