The numerous family of the Paguri, or Hermit crabs, is also condemned by its formation to lead a parasitic and robber-life. The fore part of the body is indeed, as in other crabs, armed with claws and covered with a shield, but ends in a long soft tail provided with one or two small hooks. How then are the poor creatures to help themselves? The hind part is not formed for swimming, and its weight prevents them from running. Thus nothing remains for them but to look about them for some shelter, and this is afforded them by several conchiform shells, _buccina_, _neritæ_, in which they so tenaciously insert their hooked tails, as if both were grown together. So long as they are young and feeble, they content themselves with such shells as they find empty on the strand, but when grown to maturity, they attack living specimens, seize with their sharp claws the snail, ere it can withdraw into its shell, and after devouring its flesh, creep without ceremony into the conquered dwelling, which fits them like a coat when they take a walk, and the mouth of which they close when at rest with their largest forceps, in the same manner as the original possessor used his operculum or lid. How remarkable that an animal should thus find in another creature belonging to a totally different class, the completion, as it were, of its being, and be indebted to it for the protecting cover which its own skin is unable to secrete! [Illustration: Diogenes Hermit Crab.] When the dwelling of the pagurus becomes inconveniently narrow, the remedy is easy, for appropriate sea-shells abound wherever hermit crabs exist. They are found on almost every coast, and every new scientific voyage makes us acquainted with new species. According to Quoy and Gaimard, they are particularly numerous at the Ladrones, New Guinea, and Timor. The strand of the small island of Kewa, in Coupang Bay, was entirely covered with them. In the heat of the day they seek the shade of the bushes; but as soon as the cool of evening approaches, they come forth by thousands. Although they make all large snail-houses answer their purposes, they seem in this locality to prefer the large Sea Nerites.