. The popular natural history . Zoology. LIMPET. (Showing underside.) most plentiful species of the British coasts, and may be found by hundreds either crawhng among the sea weeds at low water, or flung upon the sands by the tide. The shell of this creature is beautifully pearly, and when the outer coating is removed the iridescent nacre below has a very lovely appearance. Jewellers and lapidaries employ these shells largely in their art, polishing them carefully and then stringing them together so as to form bracelets and necklaces, or affixing them as ornaments to various head-dresses. The w
. The popular natural history . Zoology. LIMPET. (Showing underside.) most plentiful species of the British coasts, and may be found by hundreds either crawhng among the sea weeds at low water, or flung upon the sands by the tide. The shell of this creature is beautifully pearly, and when the outer coating is removed the iridescent nacre below has a very lovely appearance. Jewellers and lapidaries employ these shells largely in their art, polishing them carefully and then stringing them together so as to form bracelets and necklaces, or affixing them as ornaments to various head-dresses. The well-known univalves, so familiar under the name of Limpets, are divided in'o several families, on account of certain variations in the structure of the shell. The first family is termed Frssurellidse, on account of the fissure which appears either at the apex or in the front edge of the shell. All the Limpets are strongly adhesive to rocks, as is well known by everyone who has tried to remove one of tht'se molluscs from the stony surface to which they clung. The means by which the animal is able to attach itself with such firmness is ana- logous to the mode in which the suckers of the cuttle-fish adhere to the objects which they seize, the formation of a vacuum, and the consequent pressure of the atmoshere, being the means em- ployed. The foot of the Limpet is rounded, broad, thick, and powerful ; and when the animal wishes to cling tightly to any substance, it presses the foot firmly upon the surface, and retracts its centre, while its edges remain affixed to the rock. A partial vacuum is therefore formed, and the creature becomes as firmly attached to the rock as a boy's leathern sucker to the stone on which he has pressed it. We now come to the curious family of molluscs called appropriately --^ - — _ ^— Chitonidae, or Mailshclls, because their ^ shells are jointed together like the pieces of plate armour. When separated from each 01 her, the plates bear a strong resem-
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
