“What curious creatures crabs are!” cried Agnes.
“They are called Crustaceous animals,” returned her mother, “because they are covered with a crust or shell; and they are said to be articulated, because their limbs are jointed so that they can throw one off without suffering much inconvenience.”
“Lobsters can do the same thing, can they not?”
“Yes, they also belong to the Crustacea, and so do shrimps, and prawns, and cray-fish, besides many other creatures you are not acquainted with. All the Crustacea have also the power of throwing off their shells when they have grown too large for them, and forming new ones, as I think I explained to you some years ago when we were speaking of cray-fish.”
Fig. 20.
Irish Moss, or Carrageen.
(Fucus crispus.)
“They must suffer a great deal of pain when they change their shells.”
“They do; and some are said even to die under the operation; but I suppose they must also suffer a good deal from the old shell being too tight for them, before they throw it off.”
Agnes now picked up some sea-weed which struck her as being like what her mother had once taken, boiled with milk, for a troublesome cough.
“It is the same,” said Mrs. Merton; “the popular name is Carrageen, or Irish moss, but it is a kind of Fucus.”