(After Hertwig.) bearing at its free upper end a stiff bristle and running out at its base into a nerve-fibre; (3) concrement-cells, which produce intercellular concretions, so-called oto liths.
In the endoderm large concretions are formed (con.).
Each renal organ is a sac lined with glandular epithelium (ciliated cell, with concretions) communicating with the exterior by its papilla, and by ce, Cerebral ganglia.
Although petroleum wells in Russia have not the depth of many of those in the United States, the disturbed character of the strata, with consequent liability to caving, and the occurrence of hard concretions, render drilling a lengthy and expensive Drilling in operation.
In this deposit the occurrence of calcareous concretions is very characteristic, as L.
Secondary products, such as glauconite, phosphatic concretions and manganese nodules, occur though less frequently than in the hemipelagic sediments.
The " Challenger " and other oceanographic expeditions have shown that on the bottom of the deep sea concretions of phosphate are now gathering around the dead bodies of fishes lying in the oozes; consequently the formation of the concretions may have been carried on simultaneously with the deposition of the strata in which they occur.
Phosphatic nodules and concretions, with phosphatized fossils and their casts, occur at various geological horizons in Great Britain.
Bands of black nodules, highly phosphatic, are found at the top of the Bala limestone in North Wales; beds of concretions occur in the Jurassic series; and important deposits are known in the Cretaceous strata, especially in the Lower Greensand and at the base of the Gault.
They consist of fine clays with nodular calcareous concretions rich in fossils.
It is the principal inorganic constituent of bones, and hence of the "bone-ash" of commerce (see Phosphorus); it occurs with fluorides in the mineral apatite (q.v.); and the concretions known as coprolites largely consist of this salt.
Evidence of the same kind is afforded by the shape of the knots and concretions sometimes present in the slate.
The concretions known as bezoar-stones, formerly much used in medicine and as antidotes of poison, are obtained from the stomach of the wild goat.
Biliary concretions, known as gall stones, are apt to form in the gall-bladder.
The presence of concretions in the gall-bladder may not only lead to the formation of abscess but also to invasion of the gall-bladder by cancer.
Larger concretions formed under other conditions are known as "bean ore."
In iron-shot sands the limonite may form hollow concretions, known in some cases as "boxes."
The "eagle stones" of older writers were generally concretions of this kind, containing some substance, like sand, which rattled when the hollow nodule was shaken.
Some regard the eclogite boulders as derived from deep-seated crystalline rocks, others as concretions in the blue ground.
The water in them is exquisitely pure, except as it is impregnated by the carbonate of lime, which often forms concretions, called according to their size, pearls, eggs and snowballs.