What is "bonnet limpet"

Bonnet \Bon"net\ (b[o^]n"n[e^]t), n. [OE. bonet, OF. bonet, bonete. F. bonnet fr. LL. bonneta, bonetum; orig. the name of a stuff, and of unknown origin.]

1. A headdress for men and boys; a cap. [Obs.]
   --Milton.
   --Shak.

2. A soft, elastic, very durable cap, made of thick, seamless woolen stuff, and worn by men in Scotland.

   And p?i?s and bonnets waving high.
   --Sir W. Scott.

3. A covering for the head, worn by women, usually protecting more or less the back and sides of the head, but no part of the forehead. The shape of the bonnet varies greatly at different times; formerly the front part projected, and spread outward, like the mouth of a funnel.

4. Anything resembling a bonnet in shape or use; as,

   1. (Fort.) A small defense work at a salient angle; or a part of a parapet elevated to screen the other part from enfilade fire.

   2. A metallic canopy, or projection, over an opening, as a fireplace, or a cowl or hood to increase the draught of a chimney, etc.

   3. A frame of wire netting over a locomotive chimney, to prevent escape of sparks.

   4. A roofing over the cage of a mine, to protect its occupants from objects falling down the shaft.

   5. In pumps, a metal covering for the openings in the valve chambers.

5. (Naut.) An additional piece of canvas laced to the foot of a jib or foresail in moderate winds.
   --Hakluyt.

6. The second stomach of a ruminating animal.

7. An accomplice of a gambler, auctioneer, etc., who entices others to bet or to bid; a decoy. [Cant]

8. (Automobiles) The metal cover or shield over the motor; predominantly British usage. In the U.S. it is called the hood. [Brit.]

   Bonnet limpet (Zo["o]l.), a name given, from their shape, to various species of shells (family Calyptr[ae]id[ae]).

   Bonnet monkey (Zo["o]l.), an East Indian monkey ( Macacus sinicus), with a tuft of hair on its head; the munga.

   Bonnet piece, a gold coin of the time of James V. of Scotland, the king's head on which wears a bonnet.
   --Sir W. Scott.

   To have a bee in the bonnet. See under Bee.

   Black bonnet. See under Black.

   Blue bonnet. See in the Vocabulary.