POLYNESIAN PORITES. 97 
There is one large specimen of this coral some 18 em. high and 14 cm. across. Many free 
edges have been produced. The earliest stock, which can be seen, is still embedded in the 
base, and is a convex mass 3 cm. in diameter. Above this, repeated growth-periods, with 
edges tending to be free, have built up the present stock. The specimen is much infested 
by calcareous worm-tubes, while openings for the syphons of molluscs, and large fissures where 
crabs lurked, are numerous. These latter are generally bordered by a free thin edge of coral, 
supported and protected by epitheca, as if the coral endeavoured to arch over and thus close 
the apertures. 
a. Zool. Dept. 81. 11. 21. 13. 
The existence of a massive Porites from Ponapé is merely recorded by Briiggemann,* but 
without any description. The naming of it Porites conglomerata Quoy and Gaimard is quite 
in accordance with prevailing custom, but in such an intricate genus as Porites this is quite 
useless. In a simpler genus such a practice might suffice to suggest some fairly close 
resemblance to the figures and description of the form which originally received the name, 
but my experience shows that in this genus this is seldom if ever the case. 
LAYSAN. 
78. Porites Laysan (31, (P. Laysana prima.) 
[Laysan, coll. Dr. Schauinsland; ? Bern Museum. ] 
Syn. Porites lanuginosa Studer, Zool. Jahrb. xiv. (Syst.) (1901) p. 423, pl. xxix. fig. 9. 
Description.—The corallum is massive, nearly regularly rounded, but with its basal surface 
flattened. The stock is attached by the centre of the base to other corals, which it thus 
overhangs. The surface is broken up into a great number of comparatively smooth rounded 
humps from 2 cm. high to 2°7 cm. across, and separated by narrow and shallow valleys. 
The lower edges are closely adherent, and creep under the base to the point of attachment. 
The calicles are about 1 mm. in diameter, a little larger on the eminences than in the 
valleys. The walls are a very open reticulum, fraying out along the top ridges in rough 
echinulations ; these give the surface a woolly appearance. The septa have conspicuous edges, 
and are echinulate ; some fuse together, and others join a columellar ring. There are six pali 
visible to the naked eye, and a central columellar tubercle. 
Professor Studer calls attention to the “P. porosa” of Verrill from La Paz, Gulf of 
California, as possibly resembling this coral. But without figures it is very difficult to say 
exactly what the Californian coral was like (see P. Gulf of California 2, p. 107). 
* Journ. Mus. Godeffroy y. (1879) p. 211. 
