INDIAN OCEAN PORITES. 227 
Putting aside the difference in growth-form and in the calicle, the facts (1) that the colour, 
(2) the texture of the section, (3) the crystalline, gum-arabic aspect of the skeletal elements 
are the same in both, and that here and there knobs occur in 6 not unlike the knobs which 
occasion the moniliform branching of a, lead me to believe that these specimens, coming as 
they do from the same locality, must be regarded as specifically identical, at least until we 
know more of the environment as a determining factor. 
b. Zool. Dept. 82. 10. 17. 213. 
236. Porites Providence Island 1. (P. Prudentis prima.) (Pl. XXXIIL. fig. 4.) 
| Providence Island, 19 fathoms, sand and coral, coll. H.M.S. ‘ Alert’; British Museum. ] 
Deseription.—The corallum is free, with short, thick body, from which blunt, truncated 
processes of varying thicknesses project irregularly about 2 cm. long. The whole is covered 
by the living colony. 
The calicles are about 1°2 mm. in diameter, only slightly pitted. The walls everywhere 
tend to be thick and reticular, with, however, a median row of frosted, jagged tips of trabecule, 
here faint, there pronounced. The reticulum is open, the pores being smooth and round. 
The septa are thick, very frosted, or echinulate and symmetrical. There are no pali, and the 
fossa is very inconspicuous. The interseptal loculi are open, and make the calicles conspicuous. 
The colour is a pale buff. There is no section. 
This coral may quite well be specifically identical with the two last described from the 
Amirantes, The habit of living, detached upon a sandy bottom, is the same in all. The 
chief difference seems to be in the character of the skeletal elements, which are here loose, 
open and crisp, whereas, in the Amirantes form, they are more granular and obscure. The 
differences in the shapes of the bodies and processes may be due to slight differences in their 
local environments (cf. P. Amirantes 3). 
a. Zool. Dept. 82. 10. 17. 102. 
237. Porites Providence Island (2. (2. Prudentis seewnda.) 
(Pl. XXXIII. fig. 5; Pl. XXXV. fig. 12.) 
[Providence Island, 19 fathoms, coral and sand, coll. H.M.S. ‘ Alert’; British Museum. ] 
Description—The corallum was apparently free, like the last. The central body has 
only encrusting patches of living coral upon it, small knobs and straggling fusing and 
sub-moniliform branches spring from it, the tips of which are undifferentiated reticulum. 
The branches may be 5 cm. long and 1°5 em. thick. 
The calicles are symmetrically polygonal, shallow and funnel-shaped, and separated by 
the low raised ridges between the conical depressions ; from ridge to ridge they may be 2 mm. 
in diameter. The walls are composed of stout, flat flakes, arranged as a network with pores. 
The septa are long, wedge-shaped tongues of thin flakes with their edges highly echinulate, 
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