In general, that which rises above the waters is only breccia, or aggregate of madreporic fragments cemented by carbonate of lime, broken shells, and sand.
On a layer of sand and land shells, five to six inches thick, covered by a fragmentary madreporic rock, rises a forest of mangroves (Rhizophora).
Madreporic marbles, presenting animal remains in the shape of white or gray spots, with regularly disposed dots and stars in the centre.
A madreporic marble known under the name of pietra stellaria, much employed in Italy, is entirely composed of star madrepores, converted into a gray and white substance, and is susceptible of an excellent polish.
In starfishes, a tube having calcareous particles in its wall, which connects the oral water tube with the madreporic plate.
Thus it will be seen that all the pedicels of all the rays are in communication, by means of a closed system of tubes, with this madreporic tubercle.
One of these nodules is much larger than any of the others, is constant in position, and is called the madreporic tubercle (Fig.
Obviously itsmadreporic rocks had been made fertile by tornadoes and thunderstorms.
So I was able to study the madreporic process that has created the islands in this ocean.
The water from the outside enters the ambulacral system through a special opening, the madreporic opening, and flowing to the tube-feet helps extend them.
The mouth, with its five strong "teeth," is on the ventral surface, and the anal opening and madreporic opening are on the dorsal surface.
Note on the aboral surface of the disk a small striated calcareous plate, the madreporite or madreporic plate.
The stomach is surrounded by a water-vascular ring, from which the madreporic canal passes to the dorsal surface, but does not open.
These are regarded by Ludwig as equivalent to so many openings of the madreporic canal; and there are developed, in correspondence with them, diverticula of the water-vascular ring.
The exact position of the madreporic tubercle in relation to the abactinal plates does not seem to have been made out.
A calcareous deposit is formed round the opening of the water-vascular canal, which becomes the madreporic tubercle[221].
The diverticulum becomes themadreporic canal, and the opening the dorsal pore.
On the oral plate in the next interradius is placed the opening of a single funnel leading into the body cavity, which Ludwig regards as equivalent to the opening of the madreporic canal (vide p.
The dorsal and right surface of the Pluteus, which extends so as to embrace the opening of the madreporic canal and the anus, forms the abactinal or dorsal surface of the future Echinus (fig.
We must suppose that eventually the madreporic canal loses its connection with the exterior so as to hang loosely in the interior, though the steps of this process do not appear to have been made out.
Here is the same madreporicplate or sieve, and the structure of the Echinus (Fig.
The water enters the madreporic body, circulates through the stone canal, the circular and radial tubes, and finds its exit through the ambulacra.
The true vascular or blood system consists of a heart or hæmal canal, which runs parallel with the stone canal from the madreporic body to the oral water tube.
The islands are for the most part high, terminating in volcanic peaks; but some are of opinion, judging from the arrangement of the lagoon, that they are of madreporic formation.
Tonga Tabou is of madreporic formation, with a thick covering of vegetable soil, favourable to an abundant growth of shrubs and trees.
The rock of which this port of Rottee is formed appeared of a madreporic nature, scattered about in huge blocks.
The tentacles are also subservient to circulation, for the water which is taken in at the madreporic body passes into all the tentacles, sometimes called on that account water-tubes.
In the Synaptae, as in all the Holothurians, the madreporic body is placed near the mouth, between two of the ambulacra, and opposite the fifth or odd one.
The madreporic body is situated on the upper surface of the disk (Fig.
Star-fish which has just resorbed the larva, seen from the back; b madreporic opening.
The madreporic plate, being calcareous, is said to act as a filter, purifying the water as it passes into the body, which it furnishes with oxygen as well as with locomotive power.
Stone-canal^: A calcareous tube leading from the madreporicplate to the ring-canal.
The holothurian has a water-vascular system, the madreporic plate being near the mouth, but not opening to the outside, and a nervous system which starts from a ring which lies around the mouth.
The madreporic plate is on the ventral surface, in one of the circular shields which surround the mouth.
Five rays, each hardly twice as long as the diameter of the body; spines running irregularly over the surface, but forming a pentagon at the middle of the disk and inclosing the madreporic plate; diameter eight inches.
To follow successfully the water-vascular system, beginning in the madreporic plate and extending through the stone-canal to the ring-canal around the mouth and thence through the arms, requires a strong glass and more skilful manipulation.
The madreporic plate is nearly in the center of the disk, and is quite conspicuous, being bordered with a circle of small spines.
Water filters through the madreporic plate and passes by the stone-canal to the ring-canal around the mouth, and thence to the radial tubes, one of which extends through each arm and is connected by a branch with each tube-foot.
Madreporic plate^: A sieve-like plate of carbonate of lime.
Water, entering by the madreporic plate, passes through the various canals and into the tube-feet, which it distends.
The ambulacra, when arranged in regular zones, are used for locomotion only in the lines running from the madreporic plate.
The madreporic plate lies at the angle of two of the arms or rays.
One of them is larger than the others, and is modified to form the /madreporic plate/.
Naturalists and navigators have been much divided in opinion as to the true origin of these madreporic islands.
The explanation proposed accounts for the known facts, as well as the present appearance of the madreporic islands.
Madreporic coasting reefs present themselves also on the eastern coast of Africa and of Brazil.
At this point the author introduces a geological cause, namely, a great subsiding movement of the soil, in which the madreporic colony is sunk under the water.
The madrepores abound in all intertropical seas, taking a considerable part in the constitution of the reefs which form the coral and madreporic islands so conspicuous in the ocean.
To the north of the Equator, the archipelago of the Caroline Islands constitutes a very considerable group of madreporic formation, comprehending upwards of a thousand, extending in a broad belt over nearly forty degrees of longitude.
We still meet with atolls in the Chinese Seas, and madreporic barrier reefs are abundant round the Marianne and Philippine Islands.
It may be asked, With what rapidity are these coral and madreporic banks formed, so as to become atolls and fringing reefs?
The western coast of Africa, and the east coast of the American continent, are almost entirely destitute of great madreporic reefs, but they abound in the Caribbean Seas.
It is from this point, as from a common centre, round which are ranged the series of madreporic isles and islets, that it will be useful, in concluding this chapter, to trace their geographical distribution.
The growth of the vast madreporic column would be finally arrested by the want of water when its summit approached the level of the sea.
It is principally on the north coast and upon the eastern flanks of the chain of West Indian Islands that the madreporic reefs show themselves in these regions.
In the Red Sea, reefs of corals exist which may be ranked among the madreporic coasting reefs, in consequence of the limited breadth of the gulf.
The usual measures in such a case were taken immediately, but outside the chain of madreporic rocks no depth could be sounded.
This feature alone was indicative of the madreporic formation of the soil, simple deposit, which was not yet, but which in time would become, an island.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "madreporic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
