The Industries of Animals (Paperback)

Excerpt: ...over it, and fertilises it. Then the couple depart in search of another Unio, to whom to confide another representative of the race. The egg, well sheltered against dangers from without, undergoes development, and one fine day the little fish emerges and frisks away from his peaceful retreat. Other animals, more respectful of property, avoid using another's dwelling until it is abandoned by its proprietor, and no reproach of indelicacy can be addressed to the Gobius minutus, a fish which lives on our coasts at the mouth of rivers. The female lays beneath overturned shells, remains of Oysters, or Cardium shells. The valve is buried beneath several centimetres of sand, which supports it like a vault. It forms a solid roof, beneath which the eggs undergo their evolution. Sometimes the male remains by the little chamber to watch over their fate. It is possible to distinguish the two holes of entrance and exit which mark his habitual passage. The Hermit-crab perhaps knows best how to take advantage of old clothes. (Fig. 19. ) He collects shells of Gasteropods, abandoned flotsam, the first inhabitant of which has died. The Hermit-crab (Pagurus Bernhardus) is a Decapod Crustacean - that is to say, he resembles a very small Crab. But his inveterate habit during so many generations of sheltering his abdomen in a shell prevents this part from being encrusted with lime and becoming hard. The legs and the head remain in the ordinary condition outside the house, and the animal moves bearing it everywhere with him; on the least warning he retires into it entirely. But the Crustacean grows. When young he had chosen a small shell. A Mollusc, in growing, makes his house grow with him. The Hermit-crab cannot do this, and when his dwelling has become too narrow he abandons it for one that is more comfortable. Fig. 19. At first enclosed in the remains of a Trochus, he changes into that of a Purpura; a little later he seeks asylum in a Whelk. Beside the...