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wimming larva of sea urchins and ophiurans, having several long stiff processes inclosing calcareous rods.

A yellowish-white calcareous freestone from the Isle of Portland in England, much used in building.

he guard of the phragmocone of belemnites and allied fossil cephalopods, whether horny or calcareous. See Illust. of Phragmocone.

Any one of several species of bryozoans of the genus Retepora. They form delicate calcareous corals, usually composed of thin fenestrated fronds.

A minute calcareous rodlike structure found both at the surface and the bottom of the ocean; -- supposed by some to be a calcareous alga.

y fishermen. See Illust. under Anomura. -- Sand canal (Zoöl.), a tubular vessel having a calcareous coating, and connecting the oral ambulacral ring with the madreporic tubercle. It appears to be excretory in function. -- Sand cock (Zoöl.), the redshank. [Prov. Eng.] -- Sand collar. (Zoöl.) Same as Sand saucer, below…

The hard calcareous deposit in the tissues of Anthozoa, constituing the stony corals.

A hard chitinous or calcareous process or corpuscle, especially a spicule of the Alcyonaria.

The calcareous or hornlike coral forming the central stem or axis of most compound alcyonarians; -- called also foot secretion. See Illust. under Gorgoniacea, and Coenenchyma. -- Scler`o*ba"sic, a.

One of the radial calcareous plates of a coral.

s annelids of the genus Serpula and allied genera of the family Serpulidæ. They secrete a calcareous tube, which is usually irregularly contorted, but is sometimes spirally coiled. The worm has a wreath of plumelike and often bright-colored gills around its head, and usually an operculum to close the aperture of its tu…

The hard calcareous or chitinous external covering of mollusks, crustaceans, and some other invertebrates. In some mollusks, as the cuttlefishes, it is internal, or concealed by the mantle. Also, the hard covering of some vertebrates, as the armadillo, the tortoise, and the like.

the scale which files from iron when hammered; -- applied as a name to various minerals. Calcareous sinter, a loose banded variety of calcite formed by deposition from lime-bearing waters; calcareous tufa; travertine. -- Ceraunian sinter, fulgurite. -- Siliceous sinter, a light cellular or fibrous opal; especially,…

Any small calcareous or siliceous body found in the tissues of various invertebrate animals, especially in sponges and in most Alcyonaria.

ssil brachipods of the genus Spirifer, or Delthyris, and allied genera, in which the long calcareous supports of the arms form a large spiral, or helix, on each side.

A deposit more or less resembling an inverted stalactite, formed by calcareous water dropping on the floors of caverns; hence, a similar deposit of other material.

Any one of numerous species of delicate, usually pink, calcareous hydroid corals of the genus Stylaster.

A division of calcareous sponges.

A genus of slender, transparent holothurians which have delicate calcareous anchors attached to the dermal plates. See Illustration in Appendix.

One of numerous calcareous processes which extend between, and unite, the adjacent septa of certain corals, especially of the fungian corals.