Hedgehog shell

Hedgehog \Hedge"hog`\, n.
   1. (Zool.) A small European insectivore ({Erinaceus
      Europ[ae]us}), and other allied species of Asia and
      Africa, having the hair on the upper part of its body
      mixed with prickles or spines. It is able to roll itself
      into a ball so as to present the spines outwardly in every
      direction. It is nocturnal in its habits, feeding chiefly
      upon insects.
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   2. (Zool.) The Canadian porcupine.[U.S]
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   3. (Bot.) A species of {Medicago} ({Medicago intertexta}),
      the pods of which are armed with short spines; --
      popularly so called. --Loudon.
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   4. A form of dredging machine. --Knight.
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   5. (Elec.) A variety of transformer with open magnetic
      circuit, the ends of the iron wire core being turned
      outward and presenting a bristling appearance, whence the
      name.
      [Webster 1913 Suppl.]

   6. (Mil.) a defensive obstacle having pointed barbs extending
      outward, such as one composed of crossed logs with barbed
      wire wound around them, or a tangle of steel beams
      embedded in concrete used to impede or damage landing
      craft on a beach; also, a position well-fortified with
      such defensive obstacles.
      [PJC]

   {Hedgehog caterpillar} (Zool.), the hairy larv[ae] of several
      species of bombycid moths, as of the Isabella moth. It
      curls up like a hedgehog when disturbed. See {Woolly
      bear}, and {Isabella moth}.

   {Hedgehog fish} (Zool.), any spinose plectognath fish, esp.
      of the genus {Diodon}; the porcupine fish.

   {Hedgehog grass} (Bot.), a grass with spiny involucres,
      growing on sandy shores; burgrass ({Cenchrus
      tribuloides}).

   {Hedgehog rat} (Zool.), one of several West Indian rodents,
      allied to the porcupines, but with ratlike tails, and few
      quills, or only stiff bristles. The hedgehog rats belong
      to {Capromys}, {Plagiodon}, and allied genera.

   {Hedgehog shell} (Zool.), any spinose, marine, univalve shell
      of the genus {Murex}.

   {Hedgehog thistle} (Bot.), a plant of the Cactus family,
      globular in form, and covered with spines
      ({Echinocactus}).

   {Sea hedgehog}. See {Diodon}.
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