224 MADREPORARIA. 
AMIRANTES AND PROVIDENCE ISLAND. 
233. Porites Amirantes gl. (P. Amirantium prima.) (Pl. XXXIII. fig. 1.) 
| Darros Island, 22 fathoms, coll. H.M.S. ‘ Alert’; British Museum. | 
Description.—The corallum is minute, round and explanate, very thin, about 1 mm. and 
0:5 mm. round the edges, which tend to curl under. 
The calicles are quite superficial, far apart, with no distinct outlines, but apparently about 
0:5 mm. in diameter ; they are visible only as scattered stars, each consisting of two or three 
straggling radial slits, small, yet deep and conspicuous. The walls which constitute the 
smooth ccenenchyma, in which the stars are sharply punctured, are frequently 1 mm. across, 
and consist of a very close angularly filamentous or slightly flaky reticulum, the bent 
angular threads being all beset with the finest echinule, only visible under a pocket-lens, 
The septa are straggling continuations of these rough threads; they fuse in the typical 
formula. The triplet and the fused pairs show only faint traces of the enclosed interseptal 
loculi, while those between the fused pairs which open into the fossa are very pronounced. 
There are no raised paliform points where the septa meet and fuse. The fossa is nowhere 
rounded, and there is no columellar tubercle. 
The section is an open round-meshed reticulum, in which trabecule and_ horizontal 
elements are traceable only in the fact that the bulk of the threads run vertically and 
horizontally. The colour is a pale buff. 
For other minute encrusting or explanate Porites, see Table III. The surface is 
perfectly smooth, and the calicles so far apart that it has hardly the aspect of a Porites. 
The septal formula, however, makes this point clear. 
a. Zool. Dept. 1904. 10. 17. 59. 
234, Porites Amirantes (¢2. (P. Amirantium secunda.) (Pl. XXXIII. fig. 2.) 
[African Island, 10 fathoms, sand and coral, coll. H.M.S. ‘ Alert’; British Museum. } 
Description.—The corallum is branching. From a short central stem, some 1*5-2 cm. 
in diameter, a few short, thick, irregularly nodulated branches diverge at wide angles (60°). 
These fork or put out at almost any angle small curving branchlets which sometimes taper, 
sometimes fork. The living layer is some 6-7 cm. deep, with a thin creeping edge some- 
times free and bending outwards. 
The calicles are deep, conical, angular, and irregular in size, up to 1°5 mm. The walls 
have everywhere a sharp, thin, frosted ridge. The sides of the deep conical depressions on 
each side of this ridge are thickly beset with short, stout, often knobbed septa, apparently 
