INDIAN AND PERSIAN PORITES. 233 
PERSIA. 
There is a series of thirteen specimens from the Persian Gulf. They seem to have all 
grown upon a muddy and pebbly bottom. Some grew on clusters of pebbles or on angular 
blocks to a good size ; others are seen to be growing on previous growths, which perhaps started 
on small pebbles, and, rolling over, supplied a base for new and larger stocks (ef. P. Ceylon 1-8). 
The normal growth, when firmly established and free from sediment, seems to have been 
to rise as solid fan-shaped ridges from a thick encrusting base. But these ridges appear to be 
broken up by deposits of sediment, and the stocks rise as irregular nodulated columns, swelling 
at the tips. Stocks so affected are full of interstices, and are usually much altered by the action 
of boring organisms. These changes in the conditions of growth lead to variations in the 
calicles. 
The best systematic treatment which I have been able to arrive at after several attempts 
is embodied in the following paragraphs. 
244, Porites Persia (31. (P. Persica prima.) (Pl. XXXIII. figs. 6a, 6b; Pl. XXXIV. fig. 6.) 
[Persian Gulf; coll. A. S. G. Jayakar; British Museum.] 
Description.—The corallum rises from a thick explanate and encrusting base into massive 
knobs, ridged across the top and down the sides. These masses are 8 to 10 cm. high, and fuse 
irregularly together. The living layer extends over the whole mass. 
The calicles are mostly under 1°5 mm., very pronounced or sharply depressed and 
polygonal. The walls are well marked, thin and sharp, faintly zigzag, very irregularly 
denticulate, and inclined to be membranous; the growing tips of the trabeculz composing the 
wall are slightly flattened and frosted. The septa, with regular formula, yet have very 
irregular upper edges and outline. They seem only to appear some little distance below the 
edges of the sharp walls, and the granules and points which represent their upper edges together 
compose an irregular ring of small septal granules round an almost equally irregular but 
complete ring of pali, These granules and pali are ragged, irregular, frosted knobs, very loosely 
grouped, yet seen by the naked eye they appear fairly regular. The fossa is large and circular, 
with a frosted tubercle somewhat deep down. On the tops of the ridges the calicles frequently 
open in a streaming lamellate reticulum without denticulations or eranules. 
The section shows the axial streaming layer in which trabeculz are barely distinguishable. 
These latter, however, become distinct and nodulated as they run out towards the sides, and 
are separated by straight rows of rounded pores. 
The colour of the unbleached coral is a light, rather yellowish brown or buff. The colour 
penetrates about 3°5 mm. into the corallum. 
This is the description of the most massive of the ridged specimens. It seems to have 
grown upon a cluster of large rounded pebbles, there being several separate patches of smooth 
2 H 
