This red coral is mentioned by Rumphius, in his Herbarium Amboinense, Vol. vi. Tab. 85. p. 264, but, as the figure he has given, is not sufficient to demonstrate its tubular texture and animal structure, I have had it more accurately drawn; and those parts in particular magnified, which may tend to illustrate the foregoing description. He mentions, that it is in great esteem with them, on account of its beautiful figure; but would be much more so, if it was not for the great difficulty they find in preserving the smallest twigs from falling off; which is the reason, I suppose, that the specimen is not more complete.
Lastly, he tells us, that it is used by the inhabitants of the Spice-islands as a principal ingredient in their medicines to expel poison: as also, that they have it in great esteem on account of its excellent diuretic quality.
Upon examining this coral in the microscope, I observed, that the outside tubes of the stem were chiefly stony, but that the inward parts were composed of as many divisions of spongy tubes, as there were of stony ones.
This I find arises from the smaller ramifications, which being spongy at the knobs, and stony in the spaces between them, are inclosed and united together into one common mass during the growth of this coral; so that both the soft and hard parts together make up the inside of its trunk or stem. When we examine minutely the two parts, that compose the branches, we find, that the knobs consist of little sponge-like tubes interwoven together, as they appear magnified at Fig. [D]; and the shank or part between the knobs is composed of stony tubes, that are more erect (See the piece magnified at [E]): these tubes appear to be branched from the lateral holes at [FF.] The Fig. [E] likewise shews the appearance of the tubes on the surface of the main stem.
The radiated openings in the little wart-like figures on the surface of the branches are guarded by eight pointed valves, as magnified at Fig. [I.]: these inclose the heads of the polype, one of which is figured at [K.]
The stem of this specimen is so intirely divested of its yellow mealy covering, that we may easily trace the manner in which the animals, that compose it, have carried up their stony tubular cells, which lie side by side along the surface. These tubes have still some marks of sponginess at particular distances, which, as they come to join together, form those irregular cross-lines, that surround the stem in several places. See Fig. [A.]
In other specimens I have observed the principal stems covered over with calcarious tubes, such as I have described in the Essay on Corallines, &c. in that species of keratophyton called Venus's Fan. Plate 26.
The sponginess of the knobby joints occasions that excessive brittleness in the lesser branches; which accounts for the difficulty, which Rumphius mentions, of getting good specimens of this beautiful coral.
I have lately seen a white pipy and stony coral with spongy knobs, which is only a different species of this genus, in the very curious cabinets of our friends Dr. John Fothergill, M. D. and Mr. Isaac Romilly, F.R.S. specimens of which they have both lately received from the East Indies. The examining of these has given me an opportunity to be more particular in the description of this coral; which seems to point out to us the great affinity there is between corals, keratophyta, and sponges.
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